I used a 0.5mm spacer plate in my old 1300cc Honda Civic (with 2" SU carb) - ran TO4 with 15-20lb boost waste gate from BMW 2002Tii.
Also ran with water injection (pressure switch mounted on the inlet plenum) - got clocked at 225km/h at a local club meeting at Pukekohe here in Auckland - not bad from 1300cc (this is when I got plate "1 OF 1" - that is now on the SVX)
Wolf in sheeps clothing - car was from show room (6 months later it was street legal machine). Torque steer was hard with 20lb boost due to uneven length drive shafts from front wheel drive.
http://en.wikipedia.org/wiki/Pukekohe_Park_Raceway