Dont think its necessary the one thats on there will be fine. It says on the write up for custom systems. not known anyone to fit one of these with there forge FMIC i wont be anyway!
 
Straighter and less dented than the standard so I would say it's worth it. I fitted one with my forge big race intercooler.
 
hmm not sure as mine doesnt go past the battery tray as battery is in boot and it goes straight. Forgot about this. This may cause some problems but sure people who have done this either had to cut a bit of the tray or move battery back a bit.
 
Whats the battery tray made of, metal? So just hacksaw a bit off to make it fit? Got a Dremmel too :D

I've just hacked sawed mine, still with OEM battery and tray. Well worth doing as it is a restriction and very roughly cast inside too.
I had to buy a new MAP sensor as couldn't remove it from the OEM pipe