I've used the kickdown cable from Lokar on two different aps and it worked great. It takes some time to get the up shift right but the adjustment is now made at the carb which is a TON easier. As far as my racing torqueflight in my '73 Dart Sport I have to agree that the 2-3 shift is pretty harsh whether it's on the converter or not. Normal driving when the rpm is under 4,000 (stall on the T/B) the converter doesn't soak up the harshness like I thought it might. I never take it out of high or 2nd until I come to a complete stop. You have to drive like it like it is a manual when downshifting, give it gas then go for the shift. Pushing the button for reverse is a little pain but not bad. It's cool to get a little momentum then you take your finger from the button and you are basically in neutral.

I have used a forward manual valve body with a Hurst Quarter Stick for 19 years in my mostly street driven car. I also have a bolt in sprag. It might be overkill but I have never had an issue with shifting over 600 hp including the shot of nitrous.

I love manual valve bodies on the street. I use reverse patterns w/ a Hurst 1/4 stick shifter.
They don't shift any more harsh than a good shift kitted stock VB. It's not even noticeable if your converter is a little on the loose side.

8sec. Mine goes "Blaaam"!