hi all im wondering whats the most power people have had out of a mk1/1.5 1.8 petrol?

im currently at 144bhp and 141ftlb of tourque, hoping to get to near 150 with the cams then 155-160 with a custom map?

how much more could i do to the car? itb conversion? nos? turbo?

its currently got st manifold, decat, stainless st cat back, pipercross viper, magnecore leads.

alex