Any idea?

Hey guys,

Yes i'm new to the celica forum and also i just bought my first 00 celica gt, I was wondering if any expert here can tell me,

When i bought the car i did'nt ask or test the car, my dad did and he brought it home for me. But he told me there a few thing need to fix,
Front glass, Motor mount(Don't have time yet to see which mount need to be replace), Shocks.

But when i test the car at idle and rev, from inside it sound super loud, i haven't try from outside point yet, anyone here have any idea if possible that my exhaust os aftermarket or stock? i think the diameter of outlet is more then 2.75 inches.