To get great low end gains, you'd have to get a Turbo or better yet, an SC. If that's not an option, get an CAI
or TPR and/or an exhaust like TRD
or TPR. All four give decent low end gains, and are even better when paired together. The gains won't blow you away or anything, but they're better than stock, and will make daily driving a bit easier at low RPMs.