you've done all that stuff to the car and not touched the engine!! that's one of my priorities, got a Superchips Bluefin remap within 2 weeks on mine!!!
Defo go for a replacement panel filter (like Green) only about £40 or so, and a remap. I've got the Superchips Bluefin, but I don't know about others. If you do get one, make sure you get it done on a RR, not just buy a Bluefin from your local Superchips dealer, as the problem I found was that the map wasn't doing what it should, until I took it on a RR, which cost me an extra £70. My Bluefin was only putting my engine up to 163bhp from 155 (which was standard figure with Green Panel filter!) so had to go to Superchips HQ in the end to sort it, not happy as its 4 hour round trip and wouldn't refund me the fuel cost! So maybe give that a miss then!! lol
Had a good luck at your car at The Pod matey and I have gotta say, it looks awesome
Just been looking at your build thread, I remember seeing it at Santa, wish I'd got an A3 now with Bose etc etc!!