PureTSX, RV6 is currently making a catback exhaust for the CU2. However, I don't think it's high on their priority list. Send them an email and express interest and ask for an ETA and pricing. Hopefully they can answer your questions. I'm hoping their catback will be cheaper than the rest, because the Mugen catback is extremely expensive, CT-Engineering catback is discontinued, and Fujitsubo is also quite expensive (and requires shipment from Japan).
Sorry if this wasn't the post you were looking for. Good luck!