Avoid the induction resistors sold on ebay..the ones that you attach somewhere to the temperature sensor...all they do is fool the ecu into thinking the engine is running cold/lean so it pumps in more fuel...bore wash, higher emissions, poor MPG.
Unfortunately getting worthwhile extra power from a non-turbo (normally aspirated) engine is hard work and very expensive for little gain. I've seen chips for the B that are advertised as giving 5-7hp more. You won't really notice much apart from crisper throttle response and more noise.
The other option is to change the engine. Any of the Alfa 2L should fit. They mostly share the same block. The hard bit is connecting up gearbox etc.
I did major work on my coupe, taking it from 211hp when I started to 310 on a rolling road, mostly through, chipping, FMIC, bigger turbo, decent air box etc. But that was a turbo car where the tuning parts existed.
Other point is that tuning/more power = more fuel burn, more running expenses and shorter engine life. Don't forget to tell the insurers as well.
This question used to come up all the time from the guys with the non turbo coupes..early euro spec ones came with the B engine. the answer was usually to sell it and buy a turbo version, cheaper and less heartache than trying to mod it.
