Porsches:
986 Boxster S. The first time ever that the Boxster posed a threat to the 911 is with the S version. More power, optional sport suspension, lighter than a 911, mid-engined. Rare because it was so expensive at the time. Get the IMS bearing mod done.
987.2 Cayman/Boxster Base or S, but especially the Cayman R. 987.2 refresh launched in 2008. You know, the recession. Not a lot of people bought these cars or many cars during that era. For obvious reasons. So they are incredibly rare, regardless of trim choice. Even better that it doesn’t have the IMS anymore. But it costs twice as much as a comparable 987.1.
996 911, but especially the Turbo variants. The Turbo doesn’t have the IMS issues. If you get a Base, S, 4S, get the IMS mod done. Excluding convertibles because 4 seat convertibles are yuck and the used market agrees. GT3 is a given, but they’re so rare and expensive that even those well off have a hard time trying to justify their prices.
997.1 911s. All variants as well. Base, S, 4, GT3, GT2. Excludes convertibles. IMS mod on the standard trims for peace of mind.
Basically, nearly all the Porsche sportscars that were produced in that time period, I would consider a classic worthy of keeping.