should I use the existing engine 1.6 or go with a motor swap  

if want to use this motor go turbo but if you want to do a swap go with the b18 or k20  

the B16 is a great platform, especially for a street car.  

see the b16 is a awsome motor but they have no torque... don't get me wrong but they are fast. and they are awsome for the track cause of there high revving power but for around town I don't feel that it does enough unless you have a couple of mods... but around town the h22a rules the show it takes everything off the line.. the b18 is good with equal torque and horsepower... but the god motors of gods is the k20.  

i agree with hondasav. drop in a k20a and your car will be the talk of the town. I plan on dropping a k20a next year into my next project car. either an eg hatch or a crx. but it depends a lot on you. if its your commute car to work or school or wherever your on the go. how often you plan on racing. go k20a if you want to go all out. id go Type R or GSR if youre looking for more power while your driving and get decent mileage.  

I wanted to go with the type R but the *** motor is so expensive. I strayed from the mitsu, but like the boost. Is there room to boost a k20 in the coupe  

I have only seen one turbo k20 and it was in the new civic si you can go to there web site its called alljapmotors or japanese motors.. I am pretty sure its turbo maybe super charged. ya when you pay the money for a serious mtor like the Kseries you don't really want to blow that up so most people just supercharge them. good luck. Peace