Im looking to upgrade me tranny because I have a stock 4L60E and we all know how they are. Now I would love to have th350 or th400 but I like haveing my overdrive and everything. So I dotn really wanna go that route. Ive seen somethings about 4l80e's but havent searched or anything to check them out even thought of building a 4l60e. What do you guys think?