New Memeber, New to me Vic

Hey all. I bought a 2004 CVLX Sport with HPP last February with 20,800 miles on it. The old couple that had it only traveled in a 5-10 mile radius from their house according to the son. It's Arizona beige, no sunroof, and a few "elderly driver scratches". Since I bought it, I removed the air intake "silencer", added some bullitt wheels from an 05 stang, and added 12,000 miles to it. I'll be looking for more advice in the future as I make the car more mine. I would like to lower the car approx. 1.5", tint, swap the rear for some 3.55 LS, get rid of the mushiness of the gearbox, and make the exhaust tone more noticeable, and black out the rear tail panel (looks too plain stock). Any advise on which routes to take for these is welcomed. By the way, I love the car!

Lowering the rear is easy since you have air suspension, the front will need lowering springs, firmer shocks all around might be a good idea.
You'll need a tune to go with the 3.55 RAR so any performance parts that are going on should be done before that point(TB, police/Marauder airbox, plenum)
Jmod the trans for better life and a little kick in the pants, there are instructions online and a video on YouTube.
For the exhaust you can take out the silencers by the rear tires and add some good mufflers like Magnaflow, or go for the Borla system, Magnaflow system or the entire Stainless Works system(long tube headers all the way to the tips).