Good advice above, nicely put STAVROS If you have a 3.9 for sale TRAY25 I am interested as I may want a slightly lower gear for track use so I can maybe use more than 3rd?
I hear 4.44 or even 4.1 maybe too low for track and especially road motorway miles? anybody?

Foreign RS has been ok with his diff so stg3 shoud be fine, maybe consider polish and peen your wheels for longer life?