The SV6 comes standard with a 2.25inch exhaust, same as the SS - so if you want to keep the pipes that size, there's no sense in swapping the system - unless you delete the centre mufflers - but then she'll drone like a pig! For a V6, I'd just swap the rear mufflers to some red back straight through mufflers or similar. There are some Autotechnica stainless ones on ebay for around $500. A few of the members here have them. This is a youtube post by SV6sidiUte -
YouTube - Ve SV6 Sidi Quad Mufflers
YouTube - SV6 SIDI new EXHAUST!!! These look to be the same unit on a sedan. I can't see if you mentioned if your ute is SIDI or not.
YouTube - ve sv6 new exhaust This one is a 2.5inch xforce cat back - have a scroll through youtube and see what you like.
You won't see much of an performance increase from either - but if you plan on any sort of forced induction or cam work then go for the freer-flowing 2.5inch, otherwise the mufflers will be fine - and a lot cheaper. You can pick up tipped Redback mild steel mufflers for around $400 and you can fit them yourself on your driveway in about 30 min. There is a 2.25inch xforce cat back (and probably others) but not worth it in my opinion. 3 inch will be too big aswell.
The other option is to pick up a set of ss mufflers with the quad tips - just as restrictive as the SV6 units but you'll pick up a set on ebay or your local exhaust shop for under 100 bucks.
I'm not a huge fan of the Advanti range of wheels - most seem to have chrome lips - I just can't stand chrome - it's a personal thing. Same deal with XHP wheels. Seen them on too many skylines and sylvias. Although having said that, these ain't bad...
Just saw these ones from ANZ Wheels also, called Nitro.
Just go with what you like the look of. It's your ute, after all - Some people love the chrome look, others like blacked out wheels, machined face wheels - whatever - it's like the argument about the pontiac front - personally, I hate that more than I hate chev grilles - but it's all a personal choice.
Also, off on a bit of a tangent, you mentioned you lowered the ute - have you thought about sway bars or coil overs? Even if you just put some fatter sway bars on her the handling improvement will be massive! The utes do pretty well out of the box, but when I put chunky sway bars on my old VY, it was like driving a completely different car - and they're not heaps expensive (as opposed to coil-overs). And no dramas fitting them on Ps.
Sorry for the essay! lol