hehe, i know how it feels to be "poor". moms retired and dad passed away 7 years ago, so i gotta work for myself. not to mention that the rest of my family are really cheap ingrates.
anyhow, by "muffler system" i guess u mean the entire exhaust. u could buy an already assembled kit from some brand like apex'i, blitz, etc. (google helps). as for the cold air intake, sure. in fact, u can even move the routing and ending location of the filter if u want, just be sure to ask the stores if they sell kits to do that.
as for when it tops out, im sure one of the other members has driven one and owned one, just wait for them to reply
gl with the car
PS: us > rich bastards