Convince me to put a TKX in my Dart

Yeah I would definitely hold off judgement on the TKX until you see that upper crossmember actually installed. Even with just the solid 1/2" thick "U" upper it's gonna end up looking different than pictured in post #16.

Absolutely. Curious how it will work in real life.

But I don't think that BHS578 is going to clear that upper box the way it's shown in the Holley picture, it's clearly meant to go over the shift plate in front of the shifter and behind that access cover. It doesn't look like it will do that in its current location.

That's my concern as well.