Okay I got your email and am ready to put forth my two cents.
1.) Most honda engines run a very long time so I wouldn't worry about that yet. (My accord has only about 75,000 you got up there fast)
2.) Lots are available for this car. Whenever you want a part just google it and you will find out if they make it or not. I ahve seen some superchargers but no turbos but I ahve not looked very long
3.)220 bhp and when you are jsut starting out with your headers/intake/exhaust you will not see much hp but you will likely feel a perfromance boost, because while it might not be increasing hp it is opening up the engine more. But once you put down the base you really don't get that much hp for your money unless you go with fi
4.)All parts have different prices. Once you decide on a part that you want google it and you will find it at its best price. Or go to ebay but beware of knockoffs. Installation is very different and is found out by jsut calling up a shop but you will want to install everything that you can. I think that saying that you installed it yourself as 5 hp no matter what. Even if you install a stereo
Hope that helps some.