Adjust the coil overs to where you want the car to sit, not by measuring the thread.
The B20 thread will give you a lot of info, basically the same as LS/VTEC just 2L instead of 1.8-
http://www.ozhonda.com/forum/showthr...cussion-thread
As for power, expect about 100kwatw, if everything is standard. Of course you would be wanting to do I/h/e, possibly cams etc so that would increase the power.
IMO I would just go for a B18C (obviously!) that way you have a bog standard starting platform for a beginner which makes the same power. I would only suggest LS/VTEC if you know what you are doing. By the time you factor in a new gearbox etc the C would be only slightly more expensive.