Radiators / Cooling System

As a rule, the standard Radiator should be more than sufficient at keeping the engine at the correct temperature with these modifications, a higher capacity radiator is advised if your going to venture further into modifications such as larger turbos running "crazy ridiculous bhp"
Due to my venturing, I opted for a "performance" alloy  radiator when the top hose join snapped on my radiator top cover. (it also worked out cheaper than a new OEM one)

Will there be a noticeable performance difference with a larger radiator?

The answer to this is quite simple - No. The radiator is there to keep the engine running cool when being driven, or raced.

Due to the larger capacity, it holds more liquid (anti freeze / summer coolant) and the larger surface area will allow the coolant to be cooled down at a faster rate, which means the engine can be driven harder and still maintain at a good running temperature (ie not too hot)

Radiators available that I know of are Blitz, and HKS, however both of these come with a large price tag attached, the Auto Bahn 88 is by far the cheapest, and I've not had any problems with it so far.

Its worth knowing (to you) that the air filter feed moulded part will not fit over this radiator as it is deeper than the standard rad, so it may either need to be modified, or a cold air intake to be fitted.