your link doesnt seem to be what you thought it would be..?...But im glad to see you found something that works for you
New member here....Hello!!Wider suspension is better, but changing wheels doesn't change the suspension. The best offset is the stock offset because it's the offset for which the suspension was designed to work. Reducing offset to "widen" the stance of the car does not generally improve handling. The suspension geometry is adversely effected. To correctly widen the track of the car, the suspension would need to be modified. And not just by changing parts, the entire geometry would need to be redone.
no you won't have any trouble with that setup assuming the wheels are made for a Subaru (5x100, correct center bore, lug nut shape)
I advise against XXR's because they're a junky cast (they break/leak/crack) and that's not enough offset for a subaru. 2011 WRX can handle 18x8.5 +48 very well. I'd use a 255/35R18 tire on it. I'm assuming you have the pulled fenders the USDM got in 09+ WRX models as opposed to the original 08 WRX fenders.
Fyi.. That dents been fixed.. Lolyou could take a picture of your car, that always works