Seeing as its the Xr2i 1.8 its going to be 105bhp? As far as I'm aware, the difference between your engine and the rs1800 engine (130bhp) is:

Camshafts, from what I've read up the RS1800 ones are the same as the standard mondeo zetec 2.0 cams

ECU, obviously as the fueling and everything is different

Possibly throttle body too.

Apart from that the engine is relatively the same, with the exhaust you've got on and the decent induction kit, it should all help in aid to get it close to the 150 mark