I have been reading alot of posts and looked at alot of pics from alot of mods. We all know that colder air will make more hp. In all the testing that I did too much air made no gains at all without adding fuel. Some mods open the top of the box and add prefilters, IMO this adds alot of cold air but disrups air flo. Its trying to pull from air from behind, above and below the horns. All the air should come from front to back with no disruptions. The changes that I made kept the air going straight back. I put four 1 1/2" bulls eye inserts at the front of the box. I found that this was a little too much air and cut off 1/3 of the air from below. If you look at the pic with the metal screen I had to cut the two outside tabs down as they were directly below the insert. For two seasons now my top speed has been 118 on the speedo. Yesterday after my final test I pulled 128 speedo in a shorter distance. This is a huge gain. Below are some pics, hope it works the same for you! The only other mods I have are clutch work, timming and plugs.