Celica Generation 6 Short Ram Intake and Drop-in Filter Power Differences

Many have wondered about the benefits or drawbacks of short ram intakes such as the Weapon-R and the Injen, and drop-in filters such as K&N and Tom's Filters. Both have their advantages and disadvantages, but as far as performance goes, you may be surprised.
Recently, I took my '99 GT to a dyno facility to see how much horsepower it put down. We ran it multiple times, once with a drop in Tom's Racing air filter and once with an aftermarket intake system that wasn't a cold air intake.
With the drop-in filter, we got a peak output of 95.3 horsepower. With the intake, we got a peak output of 95.8 horsepower. Only a .5 horsepower difference. Take into consideration however, that we had the intake sticking out of the engine bay to draw in somewhat cold air. If you have a short ram intake with the hood closed, your performance may suffer a little bit more because of the hot air being drawn in. A heat shield or custom enclosure may help this problem.

What it all comes down to is preference. Some people like the look of the expensive, or not so expensive intake systems. They look good under the hood and also sound good when you're driving. Others prefer practicality and ease of maintenance. That's the reason I use a drop in Tom's Filter. It also cuts down on exhaust noise so you don't draw extra attention from the police. However, it won't draw attention under your hood because you still have the stock airbox. Many times people ask me, "Why haven't you got an intake?" I always tell them that the drop in filter is just as good.
Performance wise, they are almost the same. Other tests in Import Tuner have also confirmed this. This is just intended to help those who may be torn between getting an expensive intake system or getting a drop in replacement filter. If you want looks and attention, get an aftermarket intake. If you want to keep it simple and don't care about what it looks like, get a drop in filter.
Keep in mind that this article isn't referring to cold air intake systems, which do provide a larger performance increase.