It will help, but not much. Kind of a band-aid approach. Most shift kit'* just use springs and such to increase the pressure inside the atx.

Not true in the least with the 4T60E. The shift kit is very involved, and quite frankly doesn't even have a spring in it other than for a small check-valve. The kit calls for pretty extensive modification of the valvebody and several different replacement/improved parts.

The shift kits for the 4T60 and 4T65 are VERY different and cannot even be remotely considered similar.

The TransGo 4T60Ejr kit is customizable in several aspects. You can pick and choose what effects and benefits you want before install. Install, however, is much more involved and is not DIY like the 4T65 shift kits.