Two Bro's vs. Leo Vince?

Unfortunately all pipe manufacturers as well as power commander say that no re-map is needed. This is 100% not true. They say it to influence a purchase.
With any pipe and PCIII combonation standard mapping will cause a loss of power and smoothness through out the tach range. This will cause the bike to"surge" as another on this thread talked about. Also in almost every case the bike will run rich to very rich which means going through petro very rapidly even while running at a significant power loss. This is especially true on VTEC's as they have a more state of the art CPU that will fight the pipe and PCIII more than your average sportbike. Hense the O2 eliminators for any PCIII install on a 6gen vfr. PCIII may have a semi custom mapping program for Leo Vince ( not sure ), if so make sure to download it and use that as your mapping sequence. It still won't be as good as a custom map but you'll be in the ballpark. It will be a gigantic step up from the generic mapping the PCIII comes with.

 

I have a Yoshi slip-on and like it a lot on my VFR. I guess it depends what you like. I do not like loud bikes so the Leo Vance or of course a Yoshi would be my recommendation. Given the noise laws most States and Cities are adopting I would again have to say the Leo Vance is the choice I would make between the two.