Have you done the "fender screw" mod? Seems to stop any rubbing
Is there any info on here for the modification?
I've done it on mine - I'm on sportline's too but I have aftermarket wheels (19 x 8.5 ET 46) although it rubbed with the standard 18s. Fender screw mod is basically the removal of a arch liner screw located just forward of the top of the wheelarch and then tucking the arch liner behind the metal tab that the screw went into. Works a treat - message me if you need more info. Also, I reckon with those mods you're likely to have way more than 270-280BHP as the majority of stage 1 tunes give 300+ and with the better breathing of the exhaust you should be easily there (even though sometimes Bluefin gains aren't as impressive as others).
Edit - just checked their website. Have a look at the dyno graphs as they quote 311BHP (although their original figure of 261 might seem high, it's not unheard of that standard cars are pushing 250BHP)
Edit (no. 2) - I'd speak to Bluefin as you can get their Stgae 2 map which will give an extra 25ish BHP and remove the check engine light too for £50 (according to their website).