No my truck is not under warrantyanymore

but I am taking my truck to the shop on sat. I would have taken it today, but i just put in some 40 series flowmaster with a down pipe it's not 2 loud yet but i heard that they have to brake-in or something or other so cant wait. Well thank's for all your help I will let him know what I think it is and i will keep you posted.
Another question would a 98 pontiac formula rearend fit on to my truck???.......my very good friend said if it fit's i can have his( he wrecked his car ) just thought i should ask thank's again.
RUDY-