It's good that you have a decent mechanic friend (and fellow VAG nut) to help you look at the car. I'm sure you won't be disappointed in your recent purchase
Get a readers ride started and uploads some pictures!
Personally would leave tuning boxes and go for a remap.
I wouldn't bother with an upgraded panel filter either. When remapping my car, we found that the standard filter would flow enough air for 200bhp. Anything north of this figure became restrictive.