Details with pros and cons are too hard to find. Too many cheap products out there to have to experiment with all of them. I'm looking for minor changes now, increasing them later as I go.
I've switched to a K&N replacement filter and will do the mod to the silencer as you described, but I'm in the research stage of the Uppipe and Downpipe replacements. I'd like to replace two of the three cats, but retain the stock muffler. Was considering the HKS versions for both, but the lower piece replaces both cats without adding one back. What do you think? Do you know of any JDM products that will replace the two lower cats with one high flow cat and fit up to the remaining stock exhaust?