OK, I have an SLK32 AMG with Robs DCAI and a EURO 65mm pulley/tune running TORCO at 105octane and a tune to match. I don't see any cost efficient mods left. Any real power from doing a complete exhaust, 25-30whp minimum? Rob claims 15 from his downpipes which are costly and then I could do a resonator delete with a Borla Sport muffler or if a better fit a Borla Turbo Pro XS. Thoughts from experience please

 

(Mustang dyno, 178 pulley, Needswings manifolds, EC tune) Getting rid of the 4 cats, the rest of the exhaust stock, was worth 15hp on my car. Open downpipes gave me 11hp more. To be clear as possible, dyno verified, 26 hp with open downpipes and stock manifolds, resonator and muffler. Afterwards I installed long tube headers. Open headers (no exhaust) 7 hp over open downpipes. Connected stock resonator and muffler, 4 hp over open downpipes. This was all with the same tune. Results could vary depending on your particular tune and unknowns. I found and replaced a leaking intercooler afterwards. I have no idea if it affected the results or not.

Les

 

Well Robs pipes at $899. remove the 4 cats. Doesn't seem cost effective to do that since it could make selling the car harder if it should come to that. I was considering this option, then removing the resonator and going with a Borla Muffler. $1000. plus labor. So you are in effect saying that Robs downpipes without cats yielded you 26hp total? Seems like a lot, he only claims 15 hp for those downpipes. Anyone done a complete like I have described. THX

 

I believe he was saying 26hp with the cutouts open, it was 15 when them closed.

I too have been debating what to do. Rob makes some high quality products. The thing I like about the downpipes, is they are bolt on replacements, so when going to sell you could switch back to stock.

I've just had a tough time trying to locate a sound clip of the catless downpipes with the cutouts closed.

 

No open pipes for my SLK32. I am looking for a good return(HP) on cash spent. It seems the exhaust offers little. Maybe with more boost the return would be higher?