[NEUMANNZZ]

the 4L80e will be an expensive retrofit.
You can get your 4l60e rebuilt with 4L65E parts or better aftermarket parts IE beast sunshell and better clutches.
When my 4L60E bit the dust I upgraded to a beast sunshell, raybestos Z-pack clutches, already had the vette servo and transgo hd2 shift kit. I had mine rebuilt locally with a 3 year 36000 mile warranty. They also installed a rebuilt torque converter and new seleniods and wiring harness. I would call around to different transmission shops(not aamco) see what they charge for a rebuild with upgraded parts mentioned above. If there parts prices are outrageous shop online for the parts. pm PBA for a good recommendaion for parts list and go here for rebuild kits: http://www.700r4l60e.com/