Any recommendations on where to purchase downpipes for 2002-2007 wrxs? Seems like most of what is being sold is for USDM cars (Invidia, Cobb, Grimmspeed etc) which requires cutting and re-welding as theirs is slightly longer.
Have been running my wrx on 91 for the last couple of months but want to switch to 98, will there be an instant difference or will it take time for the car to "learn" the higher octane?