I think it may be possible to modify a Turbo 400 shift kit.. but I don't know.. there is that one modifing thing for vacuum, but I would like to see it in person to see exactly what it does. It may only be some POS that only modifies the vacuum to the modulator, or it could be something cool.. but yeah. Right now, there isn't a single thing that is made for our transmissions. It is very possible that mods for the 4T60-E could fit onto our trannies.. but then again they are completely different.. so who knows? Maybe drilling out the valve body or something.. HD-Clutches.. idk. Nobody has modified our trannies... but if you think of something, I will probably be apt to going in on a group buy [of course if it price is right]. Take a look at your FSM [you DO have an FSM, right?], look at the fluid flow diagrams and such for your tranny. See what you can find that could be modified. You know what reg. shift kits include? Well, check those out, and see what you can do.
'89 SSE - GX3 -190k, 155k on body - Back for another ride.