Cheers Pete, yeah I am pleased with it, just so much nicer to drive now! Really highlighted how crap the standard map was. Had to travel down to Gloucester with work today, was great on the motorway much stronger overtaking power.
It's been mapped for 97+ Ron, but I already use that religiously anyway. Its not been on the rollers so I couldn't tell you exact figures. Andrew said (and don't quote me on this in case I misheard anything he said!) the standard boost was 0.9 which he's increased to 1.1. The standard figures are 255bhp and 288lb-ft, so I'm now maybe around the 275bhp and 320lb-ft. Bearing in mind it's the stock exhaust so I certainly wouldn't expecting to be making more than that.
As I say, the extra power, whatever that may be, is almost an added bonus, it was worth it just for the smoother/stronger power delivery. As I said in original post, anyone who has this model seriously needs to consider a remap. I really struggled to find information on the WRX-S, so thought this may be useful info for fellow owners.