I run a older 5857 billet.It has all was spooled better than the stock,even with stock long block,and convert .It really came alive after I turned the boost above 22lb.
Im no tuner and it took a good turbo, TT chip with 49 ib injectors and Alky to get me into the low 12 ET.I added a 206 roller stage 1 trans and 2800 convertor went 11.87 then a newB mistake and I broke it.
I have not been to the track for two years (closed for repaving) with my new engine,very close build to Nigel's, I hope I can get a 11.5 ET
I know these billet turbos are big $$ ,it made a my car run really good with a novice tuner ,me.
If your not convinced new turbo tec works go drive a new 2 liter Subaru or Ford Eco boost.
P.S Nigel that's the fastest 5858 ET I have seen ,good job .