i have trust t517z 8cm. i like it. strong mid range power. peak power also not bad. here is some info from a old thread.
517Z's(not mine), 2860R, HKSGT2530@24psi and 2860R on std manifolds@26psi my t517z 8cm on 20psi.
At 95km/h, 85kw 95kw 90kw 85kw 111kw
At 112km/h, 105kw 140kw 130kw 130kw 208kw
At 128km/h, 155kw 240kw 200kw 200kw 275kw
At 145km/h, 255kw 305kw 296kw 317kw 305kw
At 160km/h, 330kw 325kw 315kw 350kw 340kw
At 178km/h, 360kw 350kw 355kw 361kw 343kw
At 194km/h, 365kw 358kw 372kw Chart stops
2 more timing = 370kw. but more knock, i don't want it. with the 343kw tune the knock only go up to 18.(no idea on track)
different support mods also make the power different:) i know t517z is not bb turbo, but my t517z has done 35000kms on it, still running strong.
hope you can find right turbo