I don't know how to do those quote thingys so hope you understand my post madness.
The HTB2 spools a tick slower then stock. Nothing major but you can feel it. Once it lights then it's on like donkey kong (ok that was lame). Towing does great. I usually tow EZ on 1 and the TST on 4/3. This just seem to work good for me and the sizes I tow (RV 8,000lbs & Boat 6,500lbs). Don't really have to worry about temps unless I'm climbing, but with the tow haul on, I can do about 70mph at 1200degrees, RPM's at 2700. That's with either trailer. But the lag does exist when towing on flat ground and you get that small hill/incline in the freeway. RPMs drop a bit, boost drops EGT's go up. So you have to lay into to keep it from lagging. Kinda bugs me and sometimes I wish it was a bit tighter. But I've learned to drive through it. But 85% of the time I'm not towing so the bit of lag doesn't bother. Daily, no trailer, EZ on 1 and TST on 6/5 or 7/6. She lights up quick but would love quicker. That's why I think the KillerB would be laggier on towing. Maybe it's just me and the way I tow. But I wouldn't want to turn the TST up to get it to light. Then the EGT's would go up and the whole situation would void it self out. I've thought about upgrading to the KillerB, but I really want twins. I think if I did do the KillerB, I'd just have to learn the towing routine all over again. Which I'm going to have to do anyway with twins. I've actually thought about using the HTB2 as the top turbo. Anyone tried it.