Cheapest place for new M75 or M78 Dana / Borgwarner gears

[6speediroc]

Hey guys,
Where are some places to get new M75 or M78 BTR gears for the lowest cost? Preferably original Dana / Borgwarner parts.
Can you even get aftermarket 4.11 gears for these?

I'm from Canada, and have a 1986 IROC camaro with the BTR M78 as an original factory axle. You can't buy new gears here in anything other than 3.73. I have a used set of 4.11 M75 gears in it now I picked up in NZ on vacation, but they are noisy. Looking for a brand new set of 4.11

Any help is appreciated!

6speedIROC in Canada

[6speediroc]

Anybody have some info?
Do I need to go to a dealer for this stuff?

Thanks!

[6speediroc]

Nobody has anything?

Where do you guys buy your rear axle gears??