Has to be cut somewhere between the cats and the axle. Does not matter where. Or drop the axle, install the test exhaust, reinstall the axle, test drive, do that until you have the system you want, finally reinstall the original system. Figure two+ hours of axle work for every iteration and it is easy to see why cutting is the only viable choice. But a Sonic sedan owner has to be willing; it is more than a day at the shop.
But this might help: TTR is offering drop springs at a price not much over what that brand sells for USED. If over half of their sales are for the sedan that should inspire more after market products for the sedan.
Laborsmith