I think its just machining as long as the screws didnt go thru the core itself you are fine.. you would know due to leakage or severe imprint on the fins under the screw hole, keep in mined that the screwes go in the fan first THEN the radiator, you DO NOT put the screws in the opposite side of the RAD and try to screw ALL they way thru the RAD to the fans on the other side.
notice the head of the screw.
notice that their are NO screws on the side opposite the fan, if you want to add another fan (push or pulling in the same direction as the other) then do the same for that side. insert the screw into the fan then into the rad.:
the paint will probably come off, even if you strip out a screw hole,. its just the mount, the core (fins) are what you want to watch out for.
PS: if you used the long screws and tried to screw them in ONLY with the case as a spacer then you may have stripped the holes OR went to far and punctured the RAD, I think it would have been hard to turn before actual puncturing,
you would only need 2 screws to hold the fans on, (may have SOME noise, maybe not)
if nounting it to the inside of the rear exhaust vent sandwhich the fan between the case and Radiator, using the fan as an exhaust .
Keep in mind the orientation of the hoses, is only limited by how you can fit it in your case, and how you want it to look aesthetically best but not required is to mount so the tubes dont have to touch but a little wont transfer TOO much heat.Edited by Fieldsweeper - 5/11/13 at 10:46am