Somehwere around £300 for the Seat Sport intercooler. Or there's one on ebay right now :)
 
do you have to have a remap every time you mod it like exhaust intercooler ect..?

Depends on the remap. Most are just generic ones, if you are paying more for a custom map like a stage 2/3 then it makes sense to do exhaust, intercooler etc.
 
Do the Pikey wheel arch mod made a big difference for me in warmer weather

take the wheel arch liner out

get a drill and a 23mm hole cutter

go to homebase or bnq and get a 9x6 louvre vent, spray it black, mark it out on the arch liner then drill a few tidy holes and rivet the grille onto the arch liner

Mine has this as standard, like louvers in the wheel arch liner
 
Mine has the air grille in the wheel arch and it doesn't even have the SMIC, so must be a standard Ibiza thing. Take it back to where you got it mapped if you're not happy. Otherwise get a faster car, or more mods :)