I'm an interior guy. i like sitting in my car and feeling like a million $$$! I also like it when people who know jack about cars, sit in my ride and go, "Whoa, what is this thing?"
Exterior is also somewhat important when wanting to turn heads or lift skirts! Not up there on my list.
Instantrice made some good points, you really can't use half of the 300HP most people try to obtain with their 240's unless its on a track. Audio is a nice bonus, until you go deaf!

Handles are always good, and actually help you in your day to day driving. As soon as i finish my interior (about another 3 weeks), I'll take pics and post em.