My TRD High Flow Air Filter arrived yesterday. Threw it in, and took a drive. I actually notice the difference. A similar filter, TOMs, dyno'd at 5HP gain, and TRD is supposed to be comparable to that. The gears seemed to shift a little smoother, and I felt a little more power. Quick way to gain a few HP, and save money on air filters, since this one is washable/reusable. I got it off of PartzNet, who I found to be the cheapest ($61 vs. $80+).

Why the TRD and not TOMs? Well, 2 reasons. First, I saw some people mention that they thought TOMs was TOO high flow, and was letting things past the filter. Second, TRD is Toyota Racing Development... I have a Lexus... may as well keep it in the family :)