TRANS GO SHIFT KIT QUESTION

Can I get a trans go shift kit and only install the portion of the kit that allows you to "grab low at any speed"?

....... My issue is that I have an old mopar performance shift kit that was put in the transmission about 15 years ago...and it is the type that replaces the seperator plate in the valve body etc. , so I wouldn't be starting with a stock valve body and don't wanna risk installing the full trans go kit hoping it would work well with the mopar performance kit already installed.

the only real issue i have with the transmission is that it won't grab low above 1400-1500 rpm, anything slightly above 1500(sometimes even slightly lower) and it'll hydraulically lock me out of 1st gear and only grab 2nd....this drives me nuts because most of the speed limits around here put me at about 1600-1700 rpm(at 40mph) so all I want to get a trans go for is to get the grab low at any speed feature...so, it would definitely be nice to be able to just install that part of the kit

thanx in advance, hopefully somebody knows cause for that feature alone, it'd be worth dropping 70 bucks on a kit :)
Why not contact the tech department of Transgo. They'll advise you what you can and cannot do. And as fishy68 says mixing different brands of kits may not work.
If my failing old memory serves me correct, I believe that Mopar Shift kits were repackaged kits from Turbo-Action.