Scrappy-
I'm just running the regular HTB2 (62mm/12 cm2). I like it and it didn't feel laggy to me at all. Before I got the TST, I ran the BullyDog + VA pressure box stack and the HTB2 dropped EGT 200-250 at WOT. I think this stack is maybe low 400 HP though
2 weeks ago I got the TST and have been playing with it and the VA. The highest settings I ran was 5x5 and 100% and frankly it scared the crap out of me! I figured heck why not romp on it? So I did and the end result all at the same time was:
-whiplash
-boost instantly at 40 psi
-EGT peaked about 1200
-stock clutch had major slippage
-smoked out 2 lanes of traffic with voluminous clouds of soot. (The guy in the red Durango that was trying to pass me on the inside looked pretty pi$$ed :-laf )
-then truck started running out of fuel
So when the boost hits 40, the clutch slips, and then the truck runs out of fuel right about the same time it tends to bark/huff the turbo.
I think the turbo would have liked it better if I cut back on the torque setting a bit since the VA gives a lot of low end already, but heck lesson learned for next time.
Since then I have been taking it easy until I get a SBC FE installed next week as well waiting on some fittings from Scotty for my pusher pump install.
I met a fellow in town here who is a member of DTR. He's running the Sledpuller 66 version of the HTB2 with a TST and Quadzilla stack and loves it. Previous to that he ran the Killer B2 version of the HTB2, but it had surging issues. Previous to the Killer B2 he had an ATS Aurora turbo that blew up in 5 minutes with the TST after he let it break in for a few hundred miles.
It would be nice to get twins, but right now I can't afford it. I'm pretty content where I'm at now and actually those upper TST settings haven't tempted me "yet" due to my experiences so far. Hope this helps!