You've gotta have some sorta differential in the rear!

An open differential... one wheeled burnouts... when the tires break loose, all the power is transferred to one wheel.
A limited slip differential (sometimes called posi-traction by other brands)... when the tires break loose, power is fairly equally transferred to the both wheels. You want some form of one of these!
A locking differential... locks up both wheels... generally not so good for turning!

The Mr. Clean car wash system is pretty good. Gets rid of most spotting... though, I still wipe down a few spots... but, just a few.

As far as waxing... I start with SafeCut. It's a polish, applied lengthwise (don't use circles like the directions say). It smooths down the imperfections in the clearcoat and gives a great, deep reflective finish. I then follow up with a protective layer of Meguiars NXT Tech Wax. It's inexpensive and readily available. The only next step up is Zaino which is far more spendy and only available directly from their website. NXT is great... easy to apply and easy to wipe off. I also use the NXT Speed Detailer for regular touchups. And, of course, a California Duster is a must have!

 

thanks for all the help, and yeah the diff. is a limited slip that saleen offers...but i am still wondering if i can now have them (my local ford dealership) instal the limited slip diff.