Mate, i saw your post and had too comment so i just joined the site and this is my first post.
I originally had Maloo mufflers bolted onto the rear, they had a nice little growl but it wasn't loud enough for me.
So I contacted exhaust shops and specialists around Australia and none of them had an answer for the VE SV6 when it came to exhausts.
Don't wanna be rude TinSnips but the 2.5" is supposed to have extreme drone.
I had lost hope and had bolted off my 2 rear mufflers and replaced them with straight pipes and was planning on just putting quad tips on them.
I then heard of the XForce 2.25" System, it has been specifically produced for the V6. I had it installed on Saturday.
Dead set amazing... looks awesome! sounds great, no drone. driven at all cruising speeds. I noticed a big performance increase instantly.
I fuel my car with Shell V-Power. I filled up this morning and drove to work just like any other day. I usually sit on 12L+/100km, i was flicking through the options this arvo on my way home and got the shock of my life when i saw 9.9L/100km and a range of nearly 800km. If this is right and its knocked off at least 2L/100km then it will pay for itself in a year.
I know i only got it 2 days ago and i don't wanna speak too soon but this exhaust is great, couldn't go any other way. The only downside so far is that is isn't as loud as I'd like it to be when idling. But it should get a bit deeper and louder in a few weeks as it breaks in.
This is for a Non-SIDI SV6 though