Get the lid and a front style ram air. IMO the Chris1313 is the best for your money as it's the biggest, but you'll loose AC. If your keeping the AC then the AC style Chris1313, Super Sucker ram air, and Fast Toys ram air all are good choices.
They're much cheaper options for the smooth bellow if you want to change from the according looking coupler you get from the factory, but there is really no gains to be had from simply changing that.
intakehoses.com and siliconeintakes.com both can get you a smooth coupler in any size you need for a fraction of the cost of the SLP one.
You might also want to check out the So You Wanna Be Fast...