First thing to do mate is get some better brakes ! No point in giving the car more power if it can't stop ! As far as tuning goes, a chip and actuator is the first thing. That'll see 180 and will transform the car. Depending on your budget then a K&N, better flowing exhaust and either a larger intercooler or a chargecooler (all in that order). If you did fit that little lot and had the car set up properly you're then over 200 horses - easily.

But, alas, then you need to bear in mind that an uprated clutch will be on the shopping list along with tyres, possible gearbox rebuild...............

Bit of advice - don't be so concerned with 'what bhp will I get'. That's pub talk bullshit and in 99% of cases only any good for saying to your mates 'my cars got more bhp than you - 'innit.........' torque is what makes the car more driveable and quicker in the real world