like ewood said, use the search drop down on the top right.
this topic has been covered multiple times.
an Si (b16a2) will drop right in, actually many b-series motor will drop right in
just start with the basics like intake, headers, exhaust, and springs/shocks.

 

http://hybrid.honda-perf.org/tech/5gtech/adrian-5g.htmcheck out this site
it has all the info your looking for

 

mustangs are fast

 

You get smart ass responses cause people are tired of answering the same question every other day, and they get bitter.

Like it's been said, there's way too many engine choices to give an answer without some sort of guideline such as a budget. Once you have a budget in mind, you can start to look into options more carefully, and then you can narrow it down to the engine series you want, and then what you want to do about turbo.

If you have unlimited funds, I'd say swap in a K20A w/ the 6spd LSD, and then turbo the snot out of it. You should be easily able to get upwards of 600HP if you have the funds for a killer turbo setup.

Easy daily driving with some reliability, I'd say go with an H22, but I'm bias in that respect.

 

i'd look for a b18... vtec would be preferred with the p72 head (gsr and sir-g motors)

this drops in realativily easily, gives a good deal more power and you'll be faster than a stock SI (vs going with the b16)

i'd suggestt looking into a turbo after this point.


if you want power "now" just boost your d-series, it's been done and you can make more power than a swap.