Re: i wanna get modding
The best way to make any engine run better is to make it breathe better. Find a local mechanic who will port and polish the head, or do it yourself. But all that porting is useless if you can get more air into the cylinder. I would also reccomend the 164S camshafts. They have a larger intake lift and are guaranteed to fit your car, since they are factory Alfa parts. Now is the problem of getting all the exhaust air out to let the new air in. I would also recommend headers (if you can find them for the 164) and bigger exhaust.
Also, if its a 5-speed, a lighter flywheel can make it rev better.
It is physically impossible to gain 20hp from intake runners alone.