The collector car market does not always reward the car that delivers the best driving experience. Famous coupes and coveted nameplates can command substantial premiums, even when a less celebrated sibling shares the same engine, chassis, or performance hardware.
For enthusiasts who would rather drive than simply admire their cars, that creates an unusual opportunity. Some overlooked sports cars offer much of the performance and character of their better-known counterparts without the same collector market premium. From open-top alternatives to forgotten performance variants, these five cars show how much capability can still be found outside the spotlight.
5
The Solstice GXP That Got A Fixed Roof And A Bigger Price
Engine displacement: 2.0-liter
The Pontiac Solstice GXP was already an unusual sports car when it arrived in 2007, pairing rear-wheel drive with a 2.0-liter turbocharged Ecotec four-cylinder producing 260 hp. But in 2009, Pontiac added something considerably rarer: a fixed roof. The Solstice GXP Coupe used the same turbocharged engine as the roadster, but replaced the fabric top with a removable targa panel. Hagerty notes that only 1,266 Solstice Coupes were built from a total of 65,724 Solstices, making the fixed roof version exceptionally scarce. Car and Driver recorded a 5.2-second 0-to-60-mph time for the GXP Coupe, 0.4 second quicker than the GXP roadster it had previously tested.
That rarity has translated into a noticeable price difference. Hagerty‘s July 2026 Price Guide puts a 2009 Solstice GXP Convertible in #3 Good condition at $10,900, while the corresponding GXP Coupe is valued at approximately $20,100 (also #3 Good condition). That is roughly a $9,200 premium for the fixed roof body style, despite both versions using the same 260 hp turbocharged four-cylinder and five-speed manual transmission.
The Coupe does have some advantages beyond rarity. Its fixed roof gives it a more distinctive profile and contributes to a slightly quicker acceleration time, while the removable targa panel still provides an open air experience when desired. The roadster remains the more affordable way into the GXP’s performance, but the Coupe demonstrates how dramatically collector interest can change the value of two cars sharing almost all of their important mechanical hardware.
4
The Porsche Sports Car That Lives In Its Own Sibling’s Shadow
Engine displacement: 2.7-liter
The Porsche Boxster and Cayman make one of the clearest examples of a sports car sibling comparison. The second-generation Boxster arrived with a mid-mounted 2.7-liter flat six, and when the 2.7-liter Cayman joined the range in 2006, it used the same basic engine, mid-engine architecture, and chassis in a fixed-roof body. For the 2007 model year, both base versions were rated at 245 hp by Porsche.
Today, the Cayman carries a noticeable premium. Hagerty‘s July 2026 Price Guide places a 2007 Cayman in #3 Good condition at $23,000, compared with $18,000 for a comparable 2007 Boxster.
That creates a $5,000 difference before considering individual mileage, condition and equipment. Recent auction results demonstrate that actual transaction prices can vary substantially, with a low-mileage 2008 Cayman selling for $29,500 in September 2026 and a 2007 Boxster changing hands for $23,500 also a few weeks ago.
That does not necessarily make the Boxster a lesser Porsche. It is better viewed as the open-top version of the same mid-engine sports car formula. The Cayman benefits from its fixed roof and greater enthusiast interest, while the Boxster provides essentially the same mechanical foundation with the added appeal of open-air driving. For someone more interested in enjoying a Porsche on the road than owning the more sought-after body style, the Boxster leaves considerably more money in their pocket.
3
Porsche’s Other 968 Has More to Offer Than Its Price Suggests
Engine displacement: 3.0-liter
The Porsche 968 may not have the same recognition as the company’s rear-engined 911, but its combination of performance and engineering makes it an intriguing overlooked choice. The Convertible retained the same 3.0-liter, 236 hp naturally-aspirated four-cylinder as the Coupe, along with the 968’s front engine, rear transaxle layout and near 50:50 weight distribution. A six-speed manual transmission was standard, while a Tiptronic automatic was also available.
Its relative obscurity also masks just how uncommon the 968 is in North America. Hagerty states that only 4,665 examples, including both Coupes and Convertibles, were sent to the region between 1992 and 1995. Of these, 2,008 were Cabriolets, according to production data from the 968 Register, making the open-top version slightly less common in North America than the Coupe. Even though fewer Convertibles were produced, the Coupe tends to receive more attention from enthusiasts.
The 968 also delivered respectable performance, with manual cars capable of reaching 60 mph in 5.6 seconds and a 156-mph top speed. The current market gives enthusiasts another reason to consider the Convertible. Hagerty‘s July 2026 Price Guide places a 1992 968 Coupe in #3 Good condition at $25,000, while a comparable Convertible is valued at roughly $15,667 to $24,333 depending on the specific model year and configuration. Recent sales show that actual prices can vary considerably, with Convertibles selling for $16,218 to $27,750 in 2026. That leaves the soft-top 968 as a potentially less expensive way into the same 236 hp Porsche sports car, while also offering the rarity and added appeal of a convertible body.
2
The Roadster That Got Left Behind
Engine displacement: 3.2-liter
When BMW introduced the M Coupe in 1998, its unusual proportions initially earned it the “Clown Shoe” nickname, but the oddball shape has aged remarkably well. Today, it is the more coveted member of the Z3 M family, even though the M Roadster shared the same basic mechanical recipe. Both versions used the 3.2-liter S52 straight-six producing 240 hp before receiving the 315-hp S54 for 2001.
The production numbers make the current preference for the Coupe particularly interesting. According to Hagerty, only 678 North American M Coupes received the S54 engine, compared with 1,564 S54-equipped M Roadsters. In other words, the supposedly less collectible Roadster was actually produced in more than twice the numbers when fitted with BMW’s more powerful engine.
That difference becomes even more compelling when looking at current values. Hagerty‘s July 2026 guide places a 2002 M Coupe in #3 Good condition at $44,467 to $67,233, while a comparable 2002 M Roadster is valued at $23,200 to $30,733. That makes the Roadster potentially thousands of dollars cheaper despite sharing the same 315-hp S54 and five-speed manual transmission.
For an enthusiast intending to put miles on the car, that price gap is difficult to ignore. The M Roadster may lack the Coupe’s increasingly valuable silhouette, but it delivers the same engine, rear-wheel-drive layout and M-car character, while leaving considerably less money tied up in the garage.
1
The E46 M3 You Can Buy Without Chasing the Coupe
Engine displacement: 3.2-liter
The E46 M3 Convertible offers a remarkably direct route into one of BMW’s most celebrated modern M cars. It uses the same 3.2-liter S54 naturally-aspirated straight-six as the Coupe, producing 333 hp, with the same rear-wheel-drive layout and six-speed manual option. Enthusiasts prize this engine for its individual throttle bodies and BMW’s VANOS variable valve timing, which give the E46 M3 its distinctive high-revving character.
The numbers also reveal why the Convertible can be overlooked. BMW produced 85,766 E46 M3 Coupes and Convertibles in total, comprising 56,133 Coupes and 29,633 Convertibles. Despite the lower production figure for the open-top model, the Coupe has become the more desirable and expensive configuration, reversing the traditional collector-car assumption that dropping the roof automatically adds value.
The current market reflects that preference, with a more substantial gap than the production figures might suggest. Looking at Hagerty’s current #3 Good valuation for a 2006 M3 Convertible, it is $25,600, while the corresponding Coupe is valued at around $42,700. That creates a difference of roughly $17,000 before considering mileage, condition, color and equipment. Actual sales can vary considerably, with a 2006 Convertible selling for $17,500 in August 2026 and another few changing hands for $27,000 in August and September.
For enthusiasts more interested in driving an E46 M3 than owning the most collectible configuration, that difference makes the Convertible worth considering.
Sources: Hagerty, Bring a Trailer, Car and Driver, 968 Register
