It's more than likely because you need tune, although pops and bangs are normally from over fuelling (running rich) where modding your car without mapping would normally make it under fuel (run lean) as far as I know, but if the car is running properly I'd guess it does just need a remap. The 2 places I've heard are good are Nr Autosport and AP tuning. Nr Autosport has got my car right now doing a load of work to it, but apprently AP are good too. Both are almost 3 hours from you but AP is just closer and according to my sat nav it would take you 2 hours 40, you'd probably make it in a bit over 2. I had to drive 2 hours to NR Autosport and leave my car there, so I had to convinced the missus to drive up with me so I had a lift back. My point is I think it's worth the effort to go to the right place. If you only wanted a remap it would be a one day job so you could just drive up and then drive back without all the hassle I had. Don't let the distance you'd have to drive influence where you get mapped. A map can make or break your car.... Literally