i had to use the s2 rad as i wanted a water cooled turbo and i hed a s2 c/c off my last car that fell off the road so i used all my s2 pipework and water pump the rad and c/c are bolted together as normal the top pins are slotted up through the slam panel and the bottom rests on the crossmember doesnt sound secure but it dont move but if i got the s1 large cooler i think id have to change to a s1 rad and and rework new pipework
cheers
kris