A few things about 400F pipes.
The MC Again pipes are very nice, the pipes from the head to collector are almost identical to the Yoshima hand bent pipes, after the collector they are different. They used to cost $475 plus $50 for delivery anywhere in the USA. I know because I was the importer. Was is the key here, there currently is no distributor outside of Japan.
The Yoshimura system is nice too, if memory serves me it was $800 a few years ago. The big problem with the Yoshimura system was that you could not fit an oil cooler sandwich adaptor with the header installed. The MC Again system had no problem and you can do an oil change w/ filter without removing the header.
I have an original Kaz Yoshima pipe on one of my bikes, and it is a pain in the ass to remove and install. For one thing the pipes aren't perfectly round where they attach to the head so each one of the exhaust pipe joint collars is ground down to fit each pipe for either the top half or the bottom half, all eight of them are different from each other so I have to look at each one for the scribe marks to make sure they go back in the same position.
The stock exhaust is tuned beautifully to the stock carbs, but it weighs a ton and can scrape when leaning right. Most café project bikes don't come with a nice set of stock pipes, so to suggest that someone keep the stock pipes is probably not going to work.
Just my two cents. I don't need any pipes at the moment