150 HP is a lot... u have to keep in mind suspension also while going for upgrade so that it can bear a heavier engine... only getting a bigger engine is not enough... otherwise u ll end up in something that might be fast but does run well...
4G93 is another option ... its 1.8 around 110 -120 HP.... its the same came in galants... for parts availibility u can do a lil servey in shershah...
even this one will cost u arnd 35 - 40k and other upgrades like suspension etc might cost u 5 - 10 k...
try to find something that has more torque... can take u faster from 50 - 100 or 120 km/h...
how often u do max speed in your car... usually 50 - 100 is the speed range that matters...
i hope i make sense...