If you plan on getting it engineered I wouldn't rush into putting the mini spool centre in because an engineer won't pass a locked diff.

I'm running a R31 LSD & went through exactly the same thought process about 1 yr ago....

Decided the extra cost of the cut down R31 was more than compensated by the increased driveability.

if you can do it your self you could get away with only spending around $200 on a not rebuilt open centre 28 spliner....worked for me

yea in perth the r31 lsd diff is hard too find

If you get a diff cut down and your ute is not engineer approved yet the whole diff assembley needs to be approved.

To combat this I used a diff out of a Corolla 30-55 series, They are available in 3.8 , 4.1 , 4.3 ratios so it gives you a chance to experiment with what ratio is best and they only cost about $50.00 - $100.00 and replacement axles $20.00

When my coupe is engineered and on the road I will have a borg warner out of a vp commodore cut down. If you want this done a place called classic restoration in perth can do this. Not cheap though.

I got a vr commodore houseing with pintara 411gears all cut down 31 spline axels and full spool shes guna rip nuts lol rated 2 850-900hp over kill but its not guna brake lol