pmurray is the man.
i was totally confused just like yourself, superchip, group n or a proper remap.
after hearing how crap superchips were and the group n being the same price as the remap i decided to go and see paul (who tried to nick my camera, don't take any valuables with you!!). that 400 mile trek was well worth it.
i suggest paying him the full whack so the job gets done properly, he spent alot of tuning time on my car and i really got my monies worth.