This horse is long past dead but I'm always late to the party anyway.
I'm thinking about a shower and doing some research. Some folks apparently have had some good success with Helton and I've lurked around Mud and this site for a while and have read good comments about Kurt. Having read this though it gives me pause for thought on buying the Helton product.
Please indulge me but this thread reminds me of a little story:
I bought a Patagonia rain jacket a full 18 years ago. I literally wore the jacket out. I sent it to Patagonia warranty repair. Their "policy" is that they will replace their product, repair it, recycle it and send you a gift card. This was an expensive jacket when I bought it....paid something like 350 bucks. I put a note in with the jacket and said if they couldn't repair to just send it back and I'd make it work.....or a gift card that would get me on my way to buying another rain jacket. Well......they sent me a gift card for $450 BUCKS on an 18 year old jacket!! I've told that story many, many times far and wide. I have become a personal ambassador.
Having written this, the OP wasn't asking for half the shop....he was asking for a pump. I assume that C/O advertises? Is there an ad budget? Why get into a pissing match over a hundred bucks? Suck it up and take funds from advertising and replace the pump. It seems like it would have been worth it. C/O would have had a company ambassador; "hey, those guys make things right!" and I would have probably bought a system. This industry is way too small to sacrifice integrity whether perceived or real.
My two cents.