are they a good idea or do they add too much weight? and if so, what are some good manufacturers?

Well I don't know a whole lot about them, but titanum is stronger than steel, and lighter than aluminum (I think don't quote me on that). But anyways they should still be stronger than what stock parts that are in your internals.Only drawback is titanium is very expensive. Hope this helps

yeah i was reading up on 'em a while ago and they can supposedly take as much pressure as is physically possible in this day and age. but there are two setbacks, they're very expensive and theyre so strong that if you put as much pressure on to them as you potentially could you'd damage yer crankshaft...