I've got a T67 on my car. Prior to that, I had been running TTC for about a year. I was very suprised how much better the T67 pulled low down compared to TTC. Obviously if you go for an even smaller turbo, the response will be even better.
If I were in 6th gear at about 2krpm, then yes, is not what you'd call responsive, but to be fair I wouldn't expect it to.
I know you're a fair way from me, but if you're ever over this way, or a meet when I'm around, you're more than welcome to have a drive.
- Edited to add, no I don't miss the sequential system at all, and if I were to start from scratch, going single would be a high priority for me.