The other thing with a larger front mount is that it may have a worse pressure drop through it (therefore less boost), but this depends on a lot of factors in addition to charge air temp. Main ones are: -
- fin pitch (how many fins per unit length, generally more fins = better perfomance but is gets to a point where the restriction to the air flow is too great and performance will drop off)
- tube size (bigger tubes have better charge pressure drop but are less thermally efficient)
- turbulator design (basically airways inside the tubes, can either be the profile of an extruded tube or extruded plates stuffed into the tubes). Used to increase the surface area for heat exchange. But like the fins, there is always a compromise.
The std CAC will probably be OK with the boost levels of G lader, higher boost levels can cope with the pressure drop for gains in performance. High boost turbos will benefit quite a bit from a front mount.
If you do decide to change, get the newest one you can. Although the basic design of heat exchangers hasn't really changed for years, newer ones will more than likely have more efficient materials and years of minor improvements. Also beware of cheap aftermarket alloy intercoolers, they may look good but some don't have proper airways (no slits in the fins). Check also the fins are properly brazed to the tubes, poor or non existant bonding will result in shite performance.
Sorry if I've been too wordy but this is actually a subject I know something about!
