Cooler is the most important mod of them all, have u got a trans cooler as well, that's a must with a convertor. With 300rwkw and std 4 speed I went 12.0
Yarra valley boxes have failed also , although mine hadn't, dion from dynamite didn't get one pass in before it failed, as well as a guy from avo, lasted a couple of weeks, so mine and 2 others I know of are still holding together.
I have heard his working on it, *Beep* will be the guinea pig for that I think, but il go to him cause his someone I trust with a 4 speed and well priced, and I also know what's in the box.
If its 10k drive in drive out, I'd rather put a built 6 speed in, but also I have yet to see any feedback from customers on Yarra valleys 1000hp box, and your right 4 th gear you can run at wot on this 4 speed.
Hey Hens that custom 4 speed I believe is not a drive in drive out price. One went in a r32gtr and the other behind a xr6 turbo, one is a member on here.