If you've already got the PPP map then it'll be around 295-300bhp already and have a sports cat on it (they rarely make the 305bhp Prodrive claimed). With a custom map, I think you'll probably see 330-335. Doubt you'll get any noticeable economy improvement but scoobs aren't about economy!
In terms of getting it done, speak to Rich (FB Tuning) or Duncan (Race Dynamix). Both should have their details in the Recommended Services section of the forum if you can't find them online