Thicker Rad mean less powerful fans?

thicker rad mean for instance - 3 rows of 13mm by 2mm Tubes compared to single row, 2 pass
FPI (fins fer inch) is where you have to decide what's the best fan for the RAD and yes ,most of the thicker RAD's are low FPI= slow~medium rpm fans

Agree; typically 'thick' rads are lower FPI, but you'll want to check and make sure first. Which rads are you using as comparison, here?

I am planing to use the xspc rx360

best rad for 800~1400rpm

I am actually going to use the XSPC Kit since its my first WC. Since because my main motivation for this set-up is silence finding fans that our "silent" has been a chore but I am probably going to go with GentleTyphon's. But I still got more reading to do!!!

You can't go wrong with this:
http://www.sidewindercomputers.com/scge120mmsic1.html
http://www.sidewindercomputers.com/no12nf54cfm.html

I liked the first one you have there I was actually looking at the 1150 GT.

http://www.jab-tech.com/Scythe-Gentle-Typhoon-D1225C12B...

Yep ..if you don't have a fan controller this may be the one to get ..all tho 1400rpm is still very comfortable