Car Decisions BRZ Sti? or keep putting money in old WRX for Track?

scruffydog

So I have a buddy that currently has a 2003 Subaru Impreza WRX. The only mods he has is what came with the car used.

Which was:
-Pro Drive Exhaust
-Pro Drive Tune up
-HKS Ground Kit
-K&N Intake
-Pro Drive Wheels
-Track Brake Pads
-Everything else is OEM

He uses it as a daily commuter but recently took his WRX to an open track in Thunderhill for the first time. Had a freaking blast out there but his car crapped out after 3 sessions due to misfiring on one of the cylinder. The car has over 130K miles - I believe it's starting to fall apart.

All my buddies seem to have fast cars (C6, 370z-me, Mini Cooper S, G35, 350z, S2K, etc) He really wants to spend some money in either, 1) fixing up his WRX for track or 2) buy a new car (Perhaps a BRZ STi) that he can enjoy in both everyday driving and on track as well.

What do you guys think?
Should he just get an everyday practical ride (Honda Civic) and throw money into turning my 2003 WRX into a track beast? As I am calculating in the cost of buying new suspension, bigger brakes, a new turbo Turbo, this is adding up fast!
Or should he just get a BRZ STi (newer, more reliable with a better platform & less things I need to fix/upgrade).

He's so lost and I guess I just wanted some insights in what's the best way to spend his money.