I use FedEx to ship to the US. Just make sure you fill out the international paper work. FYI anything over $250 and the receiver in the State pays tax.
As for your Borla exhaust it should be no problem just don't have it sent with UPS as they will gouge you for brokerage. Have the sender list a price

you paid on an invoice and delcration for customs. Anything over $50.00 that's {not} a gift you will pay PST and GST. Only way to get away from the brokersage is to have it sent to a place like CBI in NF,Ny.Then you can pick it up yourself and save the brokerage. Still I would have it sent via FedEX.
Hope that helps some.
Manny