what sort of power could i get from a 1.8 silver top engine (whats a escort lx or ghia? 105ps or 115ps)

with 4-2-1 manifold/exhaust and air filter?

could i change the cams to 130ps ones from the xr3i? or change the throttle body?

whats things could i change just to get abit more power from it?

also when ive sourced a donor car, i think im going to replace the conrod bolts for arp products..just for the safe factor...