I've tracked a 944 turbo for many years with great success. They are very reliable cars if well maintained. I'm up to 150k and still on the original turbo. In stock-ish form (i.e., with a chip and cat delete) they are comparable in performance to an E36 M3.
There are two challenges to running one as a track car. #1 is that you must start with a car that is well prepared and up to date on maintenance. If you start with a rat or a street car that hasn't seen much use in recent years, you’re likely to become frustrated as each weekend brings a new issue brought on by deferred maintenance. Sounds obvious, but you see this scenario frequently. #2 is that it is very easy to dramatically increase HP with a larger turbo, MAF conversion, piggyback computer, etc. Several vendors sell kits with all of the required components. Many people install this stuff and fail to get the car running properly with a stable, baseline tune. This obviously begets problems. If everything is sorted properly, the addition of 100+ rwhp creates a whole lot of issues when the car is used on the track – brakes, heat dissipation, etc. I wouldn’t bother.
Leave it pretty stock under the hood and it’s a giant killer that will treat you well. Upgrade the suspension with coilovers and it’s even better. An S2 slots well into several race classes, but is a little lacking as just a fun track car IMO unless the car has had a lot of weight removed. 208hp in 3000 lbs is a little meek by modern standards. The 968, with the extra 30hp, is a good alternative.