For the Mazda I am thinking about getting a later model Hilux Rear Axel including Disc brakes. Then shortening the Axles and tubes and fitting a ARB Airlocking Diff Centre. http://www.aussiediffs.com.au/product_info.php?products_id=112 ARB Hobart *UPDATE* 1FEB17 A Limited Slip Differential from an ED Falcon came up on Gumtree for a good price with the advantage of the stud patern being 114.3 X 5 which is the same as the RX-7 so will match the front RX7 Hubs. The axle assembly is far too wide at 1550 but this offers plenty of axle to either cut it down and re-spline or purchase 28 spline 9' axles the right length as many options are available.
Messings around in the shed