When pulling the bumper for the intercooler I also looked into the best way to install a FWI. I was hoping to avoid hacking on the brace that is in the way, and also hoping to avoid having to pull the bumper to ever get to the filter. I started searching the K&N site and came across the RU-2510. It has a 4" opening, but is not much wider around and very short. With it I can slide it into the fender from the engine compartment with a little manipulation. You could even make it easier by enlarging the hole a little. From there it was just a matter of trimming the roof flashing piece and screwing it down, and connecting the 4" piping. It saves a bit of time, money, and effort by cutting out the entire process within the fender. IAT readings have been ambient.
RU-2510 - K&N Universal Air Filters, Universal Rubber Filter
You can buy it straight from K&N. I bought it off of Amazon for $32 with free shipping.
