R-Tech. They're in Hinckley in Leicestershire, so maybe a little trek for you, but people travel there from all corners of the country. They're pretty much regarded as the best TFSI mappers about.
Get an oem revision G dv. Make sure the pcv and cam follower are healthy.
Yes, you'll hear the turbo boosting more.
R-Tech maps are fully custom, so you'll get the best output from your hardware. Depending on your budget it'd be worthwhile getting a couple of things done before you go down.
The biggest restriction to take care of is the exhaust. The cheapest way of improving that is a pre cat delete. If you're flush, a full exhaust with decat or sports cat and bigger downpipe is ideal - you'll create loads more flow and reduce egt's, which means more boost can safely be mapped in. Pre cat delete is good, as it removes some restriction, but until you get a bigger downpipe it's still restricted considerably.
If you're after noise, a decent intake like Revo, ITG or Ramair will tick that box, as well as improving flow. The standard airbox isn't anywhere near as much of a restriction as the exhaust, but it'll give you a bit more power.
Then you're into the realms of an upgraded fuel pump, intercooler etc. You'll gain loads of mid range with an uprated pump. Better IC will aid flow and keep things cooler.
