I just got the Air Filtration System for my Baja Turbo. The retail is near $40 but I got it from autowebaccessories.com for $30.
I don't know who designed this but they were not Baja Owner Friendly. The filters are only good for 7500 miles or 12 months according to the directions. For most people that's going to be 2 sets per year --- at $40 a pop at the dealer that's ridiculous. For me it's 6 (I do about 40,000 miles per year) or $240 retail for air filters.
On top of that, installation is tedious. They go into the air handling system behind the glove box. That means you empty the glove box, remove 11 screws, 2 wiring harness plugs, 1 trim panel and the entire glove box & it's mounting assembly. We're not talking 10 minutes & away. Even getting the glove box to drop to get access to a couple of the screws is painful as the "knockout pins" don't knock out.
I put mine in tonight so I can't really say if it makes a difference (although I was surpised to see how much debris was in the air housing already (my car is 6 weeks old).
Oh, this is not a case where you can just leave them in & not replace them if you decide you don't want the extra filtration --- they've got warnings about air flow reductions requiring the removal & replacement of the filters.
Just an FYI,