i'm new here and i have a 97 bonneville with a 3.8. i was wondering what can i do to get more hp out of it. and wat is a good muffler to put on it to get a nice sound. any help would be great. thanx.

Welcome! Lots of parts are available:

180* thermostat for starters
aftermarket intake (search for "rice pipe")
any kind of performance muffler (Magnaflow, Flowmaster both sound great)
Hi-flow CAT
headers are available for your engine
rockers and other internals..etc etc.

Check intense-racing.com and search around this forum with the search feature, you'll find plenty of ideas.

Everything you need to know about your car to get started is in the performance area of the techinfo section. There'* a lot of info there so get a sandwich or diet coke or beer or something and get comfortable. It is great reading.