h22a is not an easy swap by any means. it fits, but it takes some custom work. for a shop to do it and do it right, your looking at about 5-6 grand all told, including motor and parts. the torque of the motor is unmatched, but you could get a much faster modified b16 or b18 for that kinda money. DO NOT, AND I REPEAT DO NOT BUY AND EBAY MOTOR, unless the person is local and you can see the motor itself. its too easy to get ripped off. and the prices i saw on there arent that competitive. go with www.flashoptions.com , www.hmotorsonline.com or www.importautosalvage.com those are the highest rated sites. or go to your local junkyards, see if they have anything. as for the cx vs. si, the biggest thing is weight. cx's are almost 300 lbs lighter than a si hatchback. the si is heavier than any other civic of the era, save for the ex coupe and sedan. but it has all the nice features- better brakes, bigger fuel tank, power sunroof, etc. so do you want comfort or do you want a few tenths? its your choice.