Ok, now i used Extreme in both my Skyline and VS to try it out.
It made a great difference to the skyline. The VS made a slight difference.
Used about $40 in the skyline on the weekend. There was hardly any knock etc. The ride was smoother, there was more pick up... That is under good heavy load session too..
I went up MT Mee, then across to Mt Glorious then over Mt Nebo, no pinging, hardly knock... I like it.
Well thats my opinion anyway...
It is definitly at the Milton and the Virginia Shell servo's...
I will keep using it too...