Check the friendlly trans builders that support this forum.
I agree with the above especially the oversized hd 2nd gear band. That band is the biggest problem with these trans in my opinion. And depending on what your trans is doing that band just might need to be adjusted, and you can adjust it without dropping the pan. The hardest part is getting the tools in there to adjust it.In your price range I would look for a build that includes a parts list like this to provide a long lasting, reliable transmission.
Billet Input Shaft
Billet Triple disc converter (Lifetime Warranty)
HD Sfi certified Flexplate
Competition Master Kit ( includes added clutches in Direct drum and in OD Brake. OD direct clutch modification and oversized HD 2nd gear band)
Billet Servo Cover
Billet Strut
Billet Anchor
Billet Accumulator Piston
Billet 4.2 Ratio Apply lever
High Pressure Valve Body
Double Deep pan with drain plug and transmission temp port