Stay with the V7, cheaper and lighter than V8 & V9, also better engines...
In fact, i'd look at a Spec C, way, way more bang for your buck, trust me.
This is listed wrong, as an RA Spec C, but it's actually a Spec C (17 inch wheel model)
http://www.trademe.co.nz/Trade-Me-Motors/Cars/Subaru/WRX/auction-209963327.htm
This is an RA Spec C
http://www.trademe.co.nz/Trade-Me-Motors/Cars/Subaru//auction-209417966.htm
Or go for a Prodrive model, if the wind ups and lack of comforts are not your thing:
http://www.trademe.co.nz/Trade-Me-Motors/Cars/Subaru/Impreza/auction-182962972.htm
http://www.trademe.co.nz/Trade-Me-Motors/Cars/Subaru/Impreza/auction-208913350.htm
http://www.trademe.co.nz/Trade-Me-Motors/Cars/Subaru/Impreza/auction-198056512.htm