easy as pie mate, the ion reg is really under-rated as a reg when infact the only difference between that and a shocker nxt reg is a spacer disc in the nxt reg (just get a stiff plastic disc and shazam)
still prefer the non-ion/nxt reg style just because of the easier stripability and not needing a deepwell socket or spanner, just allen wrenches that everyone has so if you lose yours, no biggie.
but thats me. in all its easy to do and will give you awsome performance
balf
edit - damn you chris...mines better though