Kippax

can anyone recommend the best gearbox/diff and engine oil for an STi5. price no object.

thanks

JIM THEO

Hi Kippax
I asked the same question before some days with no answer.
After a search I decided:
Castrol Syntrax 75-90 semi synthetic for the gearbox (for smooth changes) and Silkolene BOA 90 LS for the rear diff, but doesn't matter if you use any good GL5 gearbox oil for the diff as it is sealed (but no sure about your car - mine is MY2000).
Hope this helps you.
JIM

Kippax

It helps alot. Thanks.

Andrew Timmins

I use Motul 300V 15W-50 for the engine.

Motul Gear 300 75W-90 for transmission and rear diff.

Superb quality and decent prices too.

Kippax

Ta

JIM THEO

Just to add something: do a search with the words "rear diff" & "gear oil" and you'll find the relative threads.
JIM