to open up the air box yes the springs will help but you will need to start jetting up the more air the more fuel so your gona have to play with it to get it right and if you get alot more air your going to have to GO BIG on the jets I also bumped my pilot jets up one size
I want to add some holes to the lid. Looks pretty restrictive stock. I know I'll have to up the mains and probably raise the needles. I've heard the springs in the dynojet teryx kit don't work when the airbox is opened up. If the springs in the dynojet brute force kit are lighter, it sounds like that kit might work.