is there just a muffler for the 91 maxima, or do you have to get the full exhaust system?? and how many kinds are there, also what parts do have to buy to make the sound more deep

 

you didn't have to start another exhaust thread...and also try using the seacrh these are ALL answered in the FAQs and archives!

but in short no there are no Maxima specific mufflers, no you don't have to buy a full exhaust system, there are 3 main brands..... SEARCH for more specific answers--> https://maxima.org/forums/search.php