Nissan 300ZX TT. Intake, exhaust and chip = 400hp at the crank and reliable enough to go over 100,000 miles easy. Again RELIABLE DAILY DRIVER. Even has goodies like speed sensitive steering, eletronically adjustable suspension, Limited slip differential ETC ETC.... Swap the differential from a NA to TT and with the above mods you will go 11's on the track real easy. It will also tear up the auto cross track.
Toyota Supra TT. This beast can be modified to 1100 HP on stock engine internals. Now that is impressive. But you can take a stock one and pull a few hoses and do some BASIC upgrades and get over 400hp at the wheels almost for free.
Both cars use only a 3.0 6cyl powerplant, which in my eyes is even more impressive.