Everything depends on how much boost you are planning to run. I have 2 friends who have h22a civics w/stock internals boosting 12-14 psi and daily drivin. All they have though are larger injectors and one has an AEM programable e-manage system and the other a hondata.But they have a really good tuner. I do know that there is a shop in town that has blown up 3 or 4 h22a preludes on only 7-8 psi. So its all about who you get to tune your car. Things that make horse power with out increasing boost-larger Downpipe, external wastegate & BOV, equal length turbo manafold, large cat back exhust system, cam gears. Remember that all horse power is, is torque times rpm divided by a constent varible of 5252. So anytime you can raise your redline you are gaining horse power. For example if your car makes 157 ft. lbs of torque at 7000 rpm thats 209 hp. Now if all you do is move the same amout of hp up the scale to 8000 rpm you get 239 hp. Thats a 30 hp increase and all you did was raise your redline. You raise your redline by puting cams in your car. But with the h22 the valves float at about 7300rpm so you would have to get streanthed valve springs and retainers also. If you are planing on high boost, i dont know any manufaturers of block sleeves. But anything over 20 psi and you will defineitly need that. You might think of getting a streanthed crank, but your h22a crank is already forged and should handle a pretty good amout of boost. The last bit of information i can give you is FIND AN EXCELENT TUNER. TUNING MAKES ALL THE DIFFRENCE IN THE WORLD. You could actualy build a high compression turbo h22a 11to1 or even 12to1 compression ratio. With the right tuning. Also a high compression engine makes alot more power and the same boost level than a low 9to1 ever will. Just remember the key word TUNING TUNING TUNING!!!