Hi lee. Sorry for my delay. I've been driving round country lanes getting totally lost for half the day and the rest of it I was wrestling an S6 cam belt in place.
The 1.8 is not a brilliant base to work from unfortunately. I would seriously consider swapping the engine for a turbo, every thing else should be a straight swap although your gearing will likely be a little lower.
With a sports exhaust, induction kit, fast road cam, sports catalyst and gas flowed head you will probably reach around 160 but a 1.8T turbo engine would get to 340bhp for the same sort of money (remap and bigger turbo with a better Diverter valve!)