Who makes a good HP marine exhaust without breaking the bank,

I have emi thunder exhaust. its all aluminum and I looked inside and it has individual tuned runners inside, real smooth, like shorty headers. I have used in the past; sierra "semi tuned" with 4 inch risers and they are far better than the sock ones, but I have no data on the gains for either set

https://www.diamondperformanceparts....oducts/emi-411

I put Stainless Marine exhaust on my little Cig20. Really happy with it!!