2007 Transmission Question

First I would like to apologize if these questions are answered elsewhere but I couldn't find them.  So with that I'm pretty sure I killed my trans this weekend, wont shift past 2nd gear.  Everything is pointing to it needing to be replaced.  I have a few questions on what I should do or get.
Like others on here I would like to get a little spin out of the back tires for fun times.  I have friends with same motor as mine, 5.3L, in a Silverado and they have no problems.  What I've read on here is b/c of torque management.  Would a different torque converter and transmission fix/alleviate this?  Basiclly I'm wondering if I should just put in a stock remanufactured 4L60E or go with a "street performance" transmission?  As a side question, has anyone done the swap to a 6 speed transmission?  Thoughts, benefits, worth the trouble?
I have a 2007 LT with Z71 package.  Have added cai, maf, and throttle body.  I have a diablo predator turner as well.

Thanks for any help and advice.

Just food for thought, The Silverado is lighter than an AV in the rear and doesn't have the same weight distribution that an AV has.
It never hurts to beef up a stock part but remember if you strengthen one part of a drive train then continue to "abuse" it, weaknesses will show up in other areas such as your differential or some other parts.
Torque management was used in the AV to try and save the borderline transmission and to help with gas mileage. Not sure if going to a 6 speed transmission is going to help you in the performance category since it was added in 2009 to improve gas mileage not acceleration.
As with most posts about performance mods to an AV I remind posters that the AV is a poor starting point to make a performance vehicle since it is a 6,000+ lb. suv built on a Suburban chassis with the aerodynamics of a brick..That doesn't mean you can't improve it somewhat but like speed shops like to say when a customer ask "How fast can you make it go?" Their reply is usually along the lines of "How much money you got?"
Some AV owners have used a Magnacharger supercharger to improve towing and acceleration without hurting the gas mileage too bad.

Thank you for the advice. 

Your mods so far don't add 10% more power or torque - a stock replacement transmission would be fine.  A higher stall torque converter would help give a bit more punch.  Torque management does hurt a bit, but Silverado's have it as well.  They can spin the tires because they have a lot less weight over the rear of the truck.