Quick spool valves do seem to work well, plenty of info out there on them stateside, if you have a high rpm limit spool time dont matter so much imo but im not sure id want to rev that expensive 3.4 to high, whats your planned rpm limit, not 7000rpm?
I think Suprafan (Andy) has just fitted one to his new setup, im looking forward to seeing how that peforms, that could be an amazing setup, big turbo and QSV
The Batmowheel stuff looks good to me, kirk put down 940rwhp on a s374, precision dont have the best reliability record, hopefully the bullseye stuff will be better, might look at trying one out myself soon.
Sounds like a nice build you are doing, good luck with it.