S15s are rad and IMO way better than the FRS/BRZ. You'll have to jump through a lot of hoops to make it legal ENOUGH to even drive it and like said above, it still isn't entirely legal. Once the car is 25 years old, that's a different story.
If you're hell bent on getting one though(or any other car from Japan), let me know and I can point you in the right direction. Just remember $$ talks... and since these are grey market imported vehicles, everything is done with cash. No financing, loans, payments etc etc. S15 Spec R with 250hp SR20 and 6spd gearbox will probably run around $20,000 depending on the car.
My connection just had two of these bad boys shipped out to the states this past week for some buyers:
