Freight on the Muzzy system is way cheaper than the Kerker from JC, they could not do the freight any cheaper than $350. Different size box was the reason they gave me when I enquired.
Nelso's Akra system as a Titanium end can with Stainless Headers

They are a trick bit of kit that would give more HP than the Kerker, if you are worries about a few HP the Akra is the pipe for you. If your more about the look and sound there is no comparison to the Kerker Meg IMHO. If not a Kerker the Muzzy for looks

would be my second pic. If I was racing it and chasing every pony round the top paddock there is only 1 system and that is the Akra.
Whilst the K-Factory, Nassert Beet and Tsukigi etc systems are super trick they are also over $2K+Freight and duty when they arrive