345kw of V8 Windsor Power
Join Date: Jul 2001
Re: best ecu chip 4 au xr8
Don't bother with so called 'power chips' or SS inductions intakes (although you already have one), they will do nothing for power levels IMO, and in fact I have seen the chips actually cost power. Only way to do it is to get a custom dyno tuned chip, preferably a chiptorque or the new SCT based AU edit. Many people also get decent results with unichips but IMO they aren't a great option.
The AU's already have a decent top end (heads, intake, TB, MAF etc) and respond really well to cam changes. A cam such as the Crane 2030 or 2031, TFS1 or some of the Crow cams will get you to well over 240kw. All up you will probably be looking at around $600 for the cam, springs and retainers, and $800 or so to fit it. Computer mods generally aren't required as these cams were designed to work with the EECIV/V system.
Porting the heads will give you some improvements, but the stock GT40P's flow quite well. I wouldn't bother with this unless you were going for a stroker, and then the money spent on porting would probably be better put towards some aftermarket alloys.