Vintage BMW Motorcycle Owners

When my R69S needed mufflers, I bought a set of stainless Epcos and regretted it almost immediately. They are ill fitting and LOUD! The guy who makes (made?) them advised me to make a shim out of a beer can to get the muffler to sort of seal where it slides over the header. I soon tossed them on the spares pile and bought a full set of Keihan headers and mufflers. I have no complaints. I agree that it's best to buy direct from Keihan in the UK. Even with shipping you will still save money by avoiding the markup if you buy them in the states. Mine arrived in about ten days. They are a little louder than the originals, but unlike the originals they don't rust out. The mufflers have not yellowed, but that does happen to the headers. If you don't like how that looks, it's easily dealt with by an occasional buffing with Autosol.

I still have the Epcos, in case you want to ignore my critique and make me an offer!

I'd rotted away several sets of stock mufflers by the mid '70s; was parking the bike outdoors year round here in New England, deep in the forest next to a babbling brook; a climate some refer to as a temperate jungle, and not exactly a conducive environment for the stock thin chrome over steel, but there was no room in house (read: shack) for both of us.
I broke that rotting muffler syndrome by acquiring a stainless steel exhaust system from Breakwell&Green, an English firm that used to advertise in Roland's old Vintage BMW Bulletin, the fit and finish were great, (you can [almost] see both bike/exhaust as they are today, 40 some years later, in the photo to the right>) and these old systems still show up at swap meets from time to time.
If your bike must live in a damp environment, SS will prove to be economic investment.

Don is correct; being stainless they turn a lovely straw color, rather than the blue that chrome does, when subjected to the high temps.
And I agree with Kurt; one may not notice a lack of a cross-over pipe, but they are there for a reason, to balance back pressure between the cylinders; BMW would never have spent the money if not deemed necessary.
Not noticing a difference with or without the cross-over is probably akin to not noticing a lack of neutral steering if using different sized tires front and rear, which many of us also fail to note, so no harm no foul.
And finally, agree with James; put those nos mufflers on the forum For Sale section, along with your current mufflers; they look like maybe the ones Bill Swirin used to make/sell, and there's still a small market for pipes that are a bit louder than stock; the returns might go a long way towards your new pipes.
Best-
George