The CG125 exhaust is a long ugly pipe, the CB100 was shorter, if you can get one, but it's not really gonna fit the bike since it was designed for a commuter and the bracketry isn't gonna match up with the Coguar unless you weld and fabricate new mounts.
Why not look up,the Bay of Fools, plenty of these bikes broken or at least get a pipe of a semi custom bike like the SR125 which is stumpy already?
You could always just google it....
I've got a pair of Screaming Eagles off a Harley in my garage that you could have but they weigh as much as yer bike. Never mind, loud pipes save lives......