Looking at replacements for 525s. Merc headers are $15k + ( for 2 sets) and I think cmi gen x are less. Here in Canada. Do they really cost that much to manufacture? Are Merc headers the best route or are Gex x a better replacement?

Stainless marine are the best replacements from a reliability stand point.

They're so expensive because there's few players in the game. I wouldn't go anywhere near a CMI product.

That mentality is why there are so few players in the game. If people aren't willing to give other manufactures a chance the number of suppliers will always be low.

I've often wondered the same-why so expensive? If it were up to me, I don't need fancy shiny/stainless headers-I'd settle for some ugly black ones if they were functional/affordable.

Because they say Mercury. The have been gouging the general boating population for decades. Merc wanted $45.00 for an o-ring for a VOS tank on my outboards. I threw the VOS tanks away and build a simpler, more reliable and most importantly a more cost effective fuel delievery system for my cat.

I sent my cmi headers, (single engine) back to them for
Pressure testing & polishing... What a F'in joke... All they did was piss me off, they passed the pressure test, like 80 bucks or so... Then the polishing? (So they say)
Nope
Came back looking worse then when I sent them with one of my water tubes bent
Long story short over 600 bucks (between shipping & there bill)...a wast of time & money!

On a side note the "main" reason I sent them was to be polished! & I told them that! But they wanted to test!
I pressure test them myself every year B4 the season starts...
Air them up, drop Them in a cut-in "1/2" 55 gallon drum, look for bubbles!
I wanted them to look new again
Or at least better then when I sent them away
I will never deal with them again
They have lost a customer (ME)!!!

ALL CMIs ARE NOT JUNK.

CMI gets a bad rap for all the 525 and similar header issues.

However, CMI submitted a spec for the 525s when they came out.
Mercury didn't like it. They wanted something cheaper.

What CMI ultimately accepted was a product that wasn't built as well, but built within the $$/spec they were willing to pay.
CMI built that spec and sold them thousands for OEM Mercury packages.

Then after the headers started to fail, CMI got the bad wrap as they everyone pointed fingers in both directions.

if you think about one pair of marine true headers - you actually have 4 headers - water jacket header sections and the exterior header. Time consuming to fab plus materials.

I talked to other header fab manufacturers in person and most will not even touch the thought of doing marine water jacketed headers and the very few that would make a true marine header, all said as far as cost goes, one company said they would not do it for under 3800 and the rest said 5 to 7 k for one pair.

One company gave me figures as they charged for materials and the mandrel bends. They charge a dollar amount per mandrel bend. When I added that up it was close to 5k as well.

I'd like to see the process, mandrel bending a tube inside a tube, do they use sand between the inner and outer tube to keep it uniform, welding the collector and flange seem to be the easy part of assembly