the 120Y BorgWarner is much bigger and stronger than the 1200's H145. I used the BorgWarner behind my L18 with nearly 200bhp in hillclimbs and supersprints, and the only thing I ever broke was an axle - but that was because of an axle tramp problem.

Get the 120Y tailshaft too - the diffs have different flanges.

Oh, and the 120Y's have bigger drum brakes. And you will notice the difference.

Or if you have fitted Stanza struts (or similar), get a KE55 Corolla diff. Its the same BorgWarner diff, and it bolts up to the 1200's springs, but it has a wider housing which perfectly matches the track increase you get from the Stanza struts - so you can run the same offset wheels front and rear without looking silly! swap the 120Y flange onto this diff and use the 120Y tailshaft. Handbrake requires some reworking as its a different setup on the Corolla. These diffs come in 3.9, 4.1, and 4.3 ratios. And have 2 different size drum brakes available - if you're looking through the wreckers, you'll spot the difference...The bigger ones definitely work better, but the small brakes would be OK too - they'd be about the same size as the 1200 drums.