unless your subie is heavly modded, you should be fine. i have never had a problem switching to ****ty gas when needed, but my friend(who has a stage 4+ wrx) does. he usally puts 93 in it, and on the way from stl to denver in KS we can only find 91. when that is the case the damn thing will not idel. but my 04 rs. with an CAI and Cat back donesn't even get nock. i think you should be fine, good luck.