After reading about them [RM headers] here it sounds like they are a good product, and I am ready to buy.
I thought the same and liked the price savings over the Comptech headers but I was very disappointed after I bought mine. The finishing of the welds on the inside of the manifold flanges where the header tubes were welded to it was poor - there was a lot of slag and roughness. I suspect this roughness would have impeded the air flow and reduced the performance increase. I spent several hours with my Dremel tool grinding the welds smooth. This is something that should have been done at the factory.
When I pointed this out to Randy Marchetti and told him how disappointed I was, I got the 'I will look into it' reply. Whether they improved their quality control or not, I don't know. What I do know is that I would not buy them again, even though they perform well. I think one is better off buying the Comptec or TAITEC headers. They may cost a bit more, but I believe you get better quality. I found (and my race shop agreed) the weld quality on my TAITEC GT Comp muffler to be first rate. I suspect the headers would be of the same quality. I have heard similar comments about Comptech.
One other thing, the RM header has the O2 sensor in the middle header tube unlike the Comptech and Taitec which have it in the collector (the design of the RM header does not allow this placement). So their headers should result in a more accurate O2 reading, lower emissions and better operation since the sensor is testing the aggregate output of all three cylinders whereas the RM tests the output of only the middle cylinder of each bank.
To make matters worse, when I had to have the front O2 sensor removed my NSX tech initially claimed it could not be done without removing the header because the sensor is very close to the firewall! Fortunately, he was eventually able to remove it, but the placement in the Comptech and TAITEC would not result in this problem.
Question, by leaving the cats and stock exhaust on, will I be less likely to have to deal with check engine light and other problems?
I initially had the cats and stock exhaust on, and I never got a check engine light or any other problems. I also never got much of an improvement in horsepower since the key to improvement with NSX headers is to install a good free flowing exhaust at the same time. As soon as I did that.....whoa! It was awesome!
But keep the cats on. I did. I don't think you will get any performance increase without them. And Mother Earth will like you for keeping your NSX clean (and mean!).
