I was struggling with the same decision. I went with the Vetter man 4 pipe exhaust instead and it fits great with the ECI cold air sump.
I called Clint to see if he had a 4 into 1, or 2 for the ECI sump and he had only a 4 into 4. Beautiful, fit perfect, sounds great. Works great except for making smoke. Evidently, there’s just not enough heat with just one exhaust per pipe. I’ve moved the injectors, upped the amount of oil, ran higher RPM’s, anything I could think of and they make OK smoke, but photographs show conclusively that those with 4 into 1, or 2 make far better smoke.
No big deal unless your purpose is for public display with others. Mine is and they just aren’t as good for that. Decided the only way to “maybe” fix it is to put 2 more injectors into the other 2 pipes. Not worth the hassle at this point.
When my ECI engine trashed itself internally at 900 hours I opted to save money by using my ECI sump on my new Superior engine that meant I wouldn’t have to redo snorkel, etc. Would I rather have the Superior sump that would work with different exhausts. Yes. Will I spend money to change sumps. And the exhaust.
Absolutely not.
Just my experience with the 4 into 4. Still a great product, but like everything else, a compromise. Reminds me of boating.