The only real "trouble" cars are the early build '07's, 08+ and you're generally good to go. Very conservatively speaking, if you're sub 300whp, you're not going to hurt the rods. My roomate's Speed is an intake/tune (~19psi) car and has been pretty damn reliable. It smokes on occasion, but it seems like a catch can would solve that. Other than that, he did a battery at 90,000 miles and tires and alignment and that's it. My plain-jane 3 was stupid reliable as well, the MZR series of motors are stout.
Just watch out for ragged out transmissions, you'll know right away when you drive it, if it feels like you're driving a tractor, move on to the next car. If you do buy a Speed3, change trans fluid to Redline synthetic, thank me later.