you dun need fenders, I got S1 headlights on my S2 with everything else standard
the slot near the fenders fit perfectly, I had to modify the grill since the S1s are bigger
basically the S1 headlights is a little big for my S2, but I made a few modifications
so the inverse of that logic is S2 headlight's would be a little small for the S1 slot
it'll leave a gap between the front of the headlights to the front bar as well as gaps with the bonnet
so overall I wouldn't suggest you change them, it's quite a hassle