True what Archon said.... considering your plans for modding, you might be best off going with the shift kit, especially since you'll probably be pulling the trans filter and it'* only a little further.... the instructions I have are pretty straight forward.
I'm having a shop do mine but I'll get there opinion of the install and post here Thursday evening.

Hawkjet,

Maybe you realize this already, but the shift kit for your 4T65E is little more than a few springs and spacers that "beef up" the pistons in the accumulator body. If you're going to drop the pan anyway to change out the filter and fluid, the shift kit is an extra 15-30 minutes work at most, as the accumulator body is right there. The ONLY watchout is to make sure the hard tranny lines to the accumulator are put back in place properly. Take digital pics as you go.

Just a note: When I shopped around for a shift kit, I settled on the Thrasher kit. For a few bucks more than TransGo, it came with a good Wix tranny filter, a GM accumulator body gasket, new accumulator piston seals, and a free T-shirt

I was getting that impression and figured it seemed like it wouldn't hurt anything to add it on general principles.

What did you notice was different after you did yours?

Yeah, the only thing is that the fluid tastes terrible

Actually I have a vacuum pump and I pull a vacuum on a rigid container while I have a hose down the dipstick tube to the bottom of the pan. The vacuum pump makes it simple.

Also, thanks for the update Martin...

That'* exactly what I was thinking

Here'* my mini-review:
http://www.bonnevilleclub.com/forum/...ic.php?t=71459

And here'* a guy who was smart enough to photo-document his install:
http://www.bonnevilleclub.com/forum/...ic.php?t=73947