Need Opinions Quick

some of you may remember my last thread about breaking my car, i had a Broken timing belt (now replaced)
In order to pass inspection, by the end of the month, i need a new water pump, new exaust from the cat back, and a new CB (?, or CD) boot...
now the problem is that he wants 325 for the new exaust.
I think thats kind of steep for the cat back, but never the less my parents told him to go ahead with it. (they technically own the car, so i cant really mod it right now, or i would have put performance exaust on it along time ago).
I told them to give me some time to post here before they paid all this money, but they apparently didn't ( i found out that they were going ahead with it all while typing this post).
What do you think about the exaust...? and i dont know if they are even putting a new muffler on it.
And whats the CB(?) boot do? :confused:

Thats the CV joint boot. It is part of the driveshaft. If it is missing or damaged the driveshaft will go bad real quick.

For that price the muffler will be replaced, probably with a shitty universal piece.

but i at least accept my muffler... im taking mine even if they replace it... i want the tip piece from it