Oil cooler and in more then most cases, everyone upgrades the radiator, so cooling is not a problem. But for the Turbo's, side IC's are just as good if you don't want to go for the looks of a FMIC. FMIC is more for looks in 90% of most cases. Sides will flow more than most turbo's out there and people wanta go with the FMIC kit for looks and style points. I'd say if your going over 550rwhp mark than the extra sizes of a FMIC will benefit you more. Plus Chip here sales a kit with piping for $1300+. Which is way worth it when you consider that avg. sides with no piping at all are $950 to 1k. Now you get looks, piping and more cooling space.