best direct bolt on swap is the 1.6L DOHC ZC engine its a complete bolt on it will even bolt to your stock tranny and you can get the engine for about $395-450...its got 130hp perfect engine to go with a small turbo.
the next one I suggest is the 1st gen B16A its not a bolt on you need to custom make your mounts or buy them from Hasport place racing...etc
some people have had hood clearance problems so I suggest you use the ZC hood it gives a little bit more clearance. The next would be the B18B/A then the B18C1/5 and finally the H22A which I completely not recommend anyone to do this swap unless you like big headaches and spending extra cash...take care



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ME LIKES TWISTIES!!!