Sean,
I've gotten back into modeling after about 15 years off and have been adding more detail to my builds. For me, I've started small, adding bits of detail here and there. Pre-wired distributor from MAD, fabbing exhaust out of K&S aluminum tubing, making an Optima battery, etc. Nothing real special, but each build gets better and better. For online retailers I use Megahobby.com, but I'm sure the guys here have other sites they like as well. My 2 cents, YMMV.