Judging by some of the posts i've read on here it's not worth paying for! Better off paying £40 for a K&N replacement filter. That's what i've got and I haven't any complaints. You get a bit more noise mid range
 
It doesn't do anything, you may see improvements with the ITG maxogen but that's 300 quid new. I had one and couldn't tell a difference.
 
I personally think the forge one is great. I had a k and n panel before hand, and it definitely feels stronger higher in the revs now. My dad and I fitted it in about an hour and it also looks great under the bonnet :D