Turbo housing

I'm searching around for a turbo to buy, I'm gonna custom build my kit. I'm looking something around a T3/4 Turbonetics. i know that is a small turbo that will be safe for my vtec prelude. What i dont understand is all these trims and houseing. I'm confused about stuff like .60 A/R compressor housing and .53 A/R turbine housing....yadda yadda yadda. If someone could just give me the low down on what all the numbers mean so that i could know what I'm looking for as a comsumer. THis is just what I have to my knowledge, correct me if im wrong but it starts out w/ T3 and then as the numbers go up, the turbo gets bigger so like a T60 is the biggest. See then I'd consider a T25 or so turbo and put in low compression pistons. I wanna build up my motor as one spring so i can race this summer in a league. Also maybe you could give me your opinion on what turbo would be best for the application. It is all stock except 2.5" custom exhaust cat back. Thanks

ok here we go..
the a/r is hte size of the turbine housing, thats where the exhaust gasses flow from the exhaust mainfold, now the bigger the a/r the more air will flow into the turbine wheel, for example a .53 ar is really small and wont flow alot of air but it will move the turbine qucikly and allow for qucik spool up but little top end, a .63 a/r will spool slower but give you more topend, the bigger the a/r is the slower it will spool but the more hp can be made, you should also see how much cfm the turbo flows, if you want to make 400hp look for a turbo that flows about 400lb/min but that will work on a built motor not a tock one, i say a t-25 or a 14b from a 1st gen gsx/tsi will be good they make up to 350hp..
btw 3' exhaust is great for turbo, try to get form the turbo back to see maximum hp..
good luck
1

what is your target horse power? now and in say 6-12months?
i prefer a higher comp like 9.5 with alittle less boost for a street car and for a race car only use like a 8.5 with more boost.
a very popular turbo now that works well for 300-just over 400hp applications is the tnetics 60-1

thanx for the replys, but isn't that 60-1 turbo a larger turbo. I was thinkin of going w/ a 3" downpipe but not sure yet cuz i do kinda wanna keep the air conditioning. If i go w/ that will that spool the turbo a lot easier? My guess is yes. Ive looked around for 8.5 comp pistons but I cant find any. The lowest i found is 9.0. I want this to be a daily driver. My plan is that i'll just run lower boost daily. I want to get a Hondata S200, to control everything, but from what I'm getting out of their website, you cant control the boost easily. I wanna get a boost controller, probably APEXi, is this a wise decision. I know a kid who has a supra, he has a manual boost controller that he just bumps up the PSI when he goes to race. that what i wanna do. So basicly my question is, will this work.....getting an APEXi boost controller work w/ the hondata