Start saving to 8 speed swap it,don't spend a nickel on your 6 speed. The 8 speed swap will give as much of a performance increase as long tubes and a tune will give you. The 6 speed is not a good transmission for racing,you'll blow it up in short order as soon as you start abusing it with some extra power. Do a search on here,there's a good thread on the swap already,that'll answer 99% of your questions,it's the thread that's several pages long.
If you're on facebook,join High Performance Rams and Tuned Rams,the hi-po guys hang out on facebook more then on here.
Figured I would throw together a brief list of info for swapping in the 8hp70 in early 4th gens… I couldn’t find a lot of this out there so some was trial by fire and then leaning on others (thanks to Alex LaBrash), as they were the biggest help. The process would be similar in earlier models...
www.ramforum.com
I used this thread to get me started https://www.ramforum.com/threads/8-speed-swap.180898/ My cost breakdown, And parts list. in Canadian Pesos! - I already have HP tuners ( not sure why anyone wouldn't ;)) - Im lifted 6.5" in the rear, so there's zero reason to get the 8 speed rear drive...
www.ramforum.com