I run twin Akra's 1 and 2 filter snorkel out and the required number of holes in the airbox I've run that set up with both Kev's fuel mod and then a PC and have run the latter for some years now.

Re the difference in pipes there is a post by me somewhere on here about I always wanted a 2/1 set up because it makes the bike look 100lbs lighter(at least) the way the bike ran was like chalk and cheese if you have the R and intend off-roading green laneing then I'd go 2/1 but if your running X and every bit of HP you can get then it's 2/2 mine runs really well could just do with more weight off.