"Chips" are a the best way for a vendor to make a part that costs a few dollars and sell it for a 5000% markup. The most widely-known "chip" mod is a small module on the IAT sensor. It relies on the idea that the colder the air coming into the engine, the more the ECU will adjust the fuel delivery to account for the denser air. The chip fools the sensor into giving a reading of a temperature that is much lower than what is actually entering the engine, which causes slightly more fuel to be delivered. In theory, it should work. In real practice, it doesn't.
Some companies will say that such a modification can produce up to a 10-12hp gain depending on the vehicle. They are able to make this claim due to variations in dyno pulls. They will run a certain vehicle on a dyno several times in stock form and take the lowest power numbers as a base. Then, they'll install their little wonder gadget and run the vehicle on the dyno several more times. They'll take the best run of those and compare the two to get the 10-12 hp "gain". On a modern engine with 250, 300, 350+ hp, a 10-12hp difference is a more than expected level of variance.
The only way to truly gain more power out of a modern engine without doing any other physical modification is to properly tune it. The cheap and dirty way to do it is through handheld tuners that plug into the OBD-II port and have pre-loaded "tunes" on them for specific vehicles. You'll find these for full-size trucks, diesels and performance cars, but not for your beater Toyota Camry. The best way is to have good software with a competent person doing actual tuning while either using a chassis dyno or doing real-world driving. Even the best software in the hands of a novice can cause terribly expensive and catastrophic results. For the RL, there is the added complexity of the unique AWD system and the fact that next to no one makes any sort of tuning software for them. There just simply isn't much of a market for it with the relatively low production numbers of the RL. Plus, if you alter the tuning software, you will void your warranty.
Let me be clear that there ARE very knowledgeable people out there who have been tuning on the J-series engines for a very long time like Bisimoto. However, you're talking VERY custom work that will be VERY expensive and often irreversible.