That's an awesome little car you have there.
If I could chime in about mods... headers are a must! If you could, post more pictures of the engine bay, specifically the front and rear manifolds and their clearance. That'll give us a better idea on what your options are.
As for a cam, hands down a cam is better than an intercooler. If I had a 5spd 3800 (getrag 282?) I would go with the biggest cam I could for the engine. Driveability isn't going to suffer at all because even the "big" cams for stock heads 3800s are still relatively small. I'd pick up something like an Intense stage 3.
Don't even bother with a GenV swap unless you're really going to try and string out every last bit of power.
