XXRs and Vossens cant really be compared? XXRs in 18s are 700ish, and OP can reuse his original tyres.
Vossens (assume 19?) are more than double that price, plus OP would need new tyres.
Worth it?? Lot of cash for an extra inch . Suppose if money was no object, then yes. But for me, couldn't justify 2.5k wheels n tyres on a 8k car.