This Turbo is my recommendation... $75
http://datsun1200.com/modules/myalbum/photo.php?lid=12197Its one of 2 Turbo's off a 2 litre twin turbo Subaru Legacy... perfect for a A12...
Keep in mind T2 turbo your thinking is off a larger engine so will be laggy compared to the std E15... Also being the E15 is EFI it will have better fuel and spark control to give better lower down driveability... The Legacy Turbo is design to work at low RPM so should make the A12 quite driveable and give good boost levels at low rpm... exactly what youll want with a small engine...
I ran a TD04 (someone gave it to me) on a completely stock A12 with A14 head with a SU carbie(and manifolds) and made 100kw atw with 16lbs boost... But it was a little laggy but was good from 4000RPM onwards... but the engine ran out of Puff at 6000RPM...
Therefore you want something that works from 2500/3000rpm to 6000rpm.
Honestly... use a bog stock A12, run this little turbo with an SU carbie and go and have some fun, youll love it!... If you want more grunt, get an A15, larger turbo, EFI and spend about $5000... instead of $500...
Take advice from someone who's done it...
http://datsun1200.com/modules/newbb/v ... =ASC&type=&mode=0&start=0