I've run the stock air box with the lid off with very good results. I actually didn't even want to switch to an open air intake but I purchased a mini battery & tray from Buschut that won't work with the stock airbox. All I did was buy an aluminum adapter on ebay for $12.00 and use an existing 4" K&N filter I have on another car (after cleaning of coarse).

I leaned out the A/F a little more, now I'm almost @ 11.5 in 4th, almost as lean as with the stock airbox but the butt dyno is telling me I am not making more power. Track results will tell the whole story. If I trap >85mph in the 8th and 109mph in the quarter it will stay on.