port/polishing a 5sfe, characteristics and bennifits? Options

[saleeka]

Im debating whether or not to have this done. I truly dont know exactly how this works, or what is done to what, but i'd like to know because it has been thrown at me to add a few hp. If anybody knows, does the characteristics of the engine change all that much? I'd assume a slightly quicker rev with a small loss in low end grunt for top end power- is this true? Also, where should I take my car to get this done? Im already getting my head gasket fixed at my toyota dealer- would they be able to do it when thats being done, or do I need to take it to a specialty shop? Anybody know how much one of these runs? Sorry for my complete ignorance on this subject but I'd love to gain the knowledge.