One of the very reason i doubt id ever go hfc or resonated decats is the extra noise. I use my 350z daily and love the sports sound it has now (toyosport cat back). Ive had noisy exhaust for the last 8 yrs (4-2-1 stepped fully merged ASP header and decat) and for the other 95% of the time, oe cats suit me just fine.
Well done on the adjustment to the MR2 also