OBX has a complete exhaust system

Originally Posted by Zsteve

based on the bends, size of the mufflers, and they might be chambered too to keep to volume low all this will keep from getting max gains. R&D is for getting the right look and fit for ease of installment and for getting the right tone they want. Also testing with different resontaors and mufflers to get the desired results so to answer your eye rolling question yes it can take more than two iterations to get it the way they want. You will see alot of companies come out now that look like all the ones that came out first. Its easy to copy someone elses work. The ones that make the most gains have little bends and use straight thru mufflers with no bends but this will cause some drone.

But if its so easy build one yourself and market it for sale.