I did 5 sprint type track days and 4 laps of the ring in my Is-f, and never had a hint of understeer. It was pretty impressive I thought given its weight, just wished I d managed to get to Donnington in it.
I was an IS-f owner, and love them. I'm only interested in the IS-F so very rarely post outside the IS-F section. Why is my opinion less valid? Anyway I'm out if this is the way it is.
The original finish is very smart, its has a very glossy, mirror like finish to it, none of the refurbished wheels I have seen come close which is a real shame. The colour is close but this mirror like effect seems to get lost.
I've purchased the dealer versions a few times and have always been happy. When I did have to claim for the IS-F :-( the process of claiming was easy, and in fact I was in receipt of funds before my the insurance pay out cash landed.
2010 is the pivotal moment for the ISF as the LSD was added, there were other small changes each model year from then on till the end. DRLs were a year later I think. It depends what's important to you.