I've got a Kakimoto on the car I have now. Great exhaust systems and they aren't that loud since they are legal exhaust here in Japan for the JCI inspections. I've got the HKS downpipe with the Kakimoto exhaust and no car on my car. Sounds very quiet at idle but once opened up its noticeably not a stock exhaust.
Downpipe nice? It looks like the stock exhaust system. No wide-mouth flange? What is that 2.5" piping? Geez, that has got to be the most boring exhaust I've seen so far. Might as well keep the stock exhaust.