yes you do have to run premium. google up sportage powerchip and tou should find it. they are located in australia.
i have to say, the last few days since i have taken off the bigger tires, i am noticing a huge difference. with the ecm, and a cold air, it has quite a bit more power than stock. and i am sure my engine has been driven fairly hard offroading. i took a buddys stock sportage for a fast cruise the other day to compare the 2. his engine even has a fresh rebuild and it wasnt close.

2000 SPORTY, DEF BOY customs, mmm....lockers, mmm... gears, mmm... double transfer case, mmm... stroker
http://www.cardomain.com/ride/2377991