b15/b16 QR25DE blocks and internals interchangeability...

[Chingon]

If anyone can answer the following for me (nico search has always blown):

b15 and b16 engine block differences (courtesynissan images certainly seem different (even starter position may be different). I've also heard the sleeves are a little thicker in the b16.

Head differences?

B15 w/b16 crank and rods feasible w/o modification? ecu issues?

b15 & b16 engine mounts or mount position identical?

b15 & b16 Transmission bolt pattern same?

b15 & b16 ecu conflicts in btwn? say b16 engine into b15 w/b15 transmission.

transmission spline to engine same?

Mechanical throttle body for either engine w/o much effort required?

b15 & b16 engine heights?

Thanks in advance.