I used to run a large front mount grs on my s2 rst. I think it was the evo 3??? I thought it performed really well.i was running 17 psi(Bit high i know!!!)on a standard cooler.then when i put the grs on i turned the boost down to 14psi.i took the motor out for the test run and the difference was gobsmacking. the only gripe i had with the cooler was that the end tabs which hold the intercooler in place were absolutley crap.Very thin and break easily.
On my mk3 xr3 turbo that i have now i bought a new large front mount radtec jobbie with the twin fans.when i opened the parcel the first thing i noticed was how perfect the welds were and how much stronger it appeared compared to the grs...not that i had a prob with the actual build quality of the grs,its just the radtec jobbie is better in my opinion.Also the TABs are much thicker and stronger! When putting it on i was expecting the same sort of improvement that i had with the grs.......but unfortunately it didnt seem it. im still happy with it though,as not only is it cheaper,it wasnt a 6 week waiting list to recieve it.
BEWARE THOUGH, when i went to fit my radtec jobbie i noticed there was loads and loads of metal filings in the END TANK!!!!!!!!!!it took 35mins of flushing out in my bath to get rid of them!!!!Could have caused some damage!!!!