AutoTrans Interceptor (4T40E 4 Speed)

Ok there is a little bit of information about it and i searched it and found a little more but how about some personal opinions.

http://www.carcustoms.net/product_info.php?cPath=265_22_32_598&products_id=296

I thought about getting one of these for my car, cause i have an automatic but know nothing about them. nor how to install it. Help please

Just like nintendo... plug n play...

easy to install then? how much of a difference are we talking about here in performance