I included the bulb chart for our Highlanders below:
Our tail lights and Stop lights are 7443. I would recommend using an LED Bulb that has LEDs all around it instead of one where the LEDs all point in the same direction. Reason is because our tail lights are designed to reflect light and if the LEDs all point out through the lense, then it will not be as bright as it could be.
Also, you want to get LED bulbs in the same collor as your tail light lense or you will not be able to see the light (very well). Our tail light lenses are red, so buy Red LED bulbs, not white.
Here is a link to the 7443 LED bulbs. This is not the same store I linked you to before, so I don't know much about them, but this will at least give you an idea of what I am talking about purchasing. If you search for 7443 LED bulb, you should find more out there.
Tail Light Brake Light Turn Signal LED Bulbs
As for buying LED turn signal bulbs, you can go with either Amber, Yellow or Red LEDs since our lense is clear for the turn signal. Again, I suggest using LED bulbs that have LEDs all around it instead of all pointing in the same direction. You should be able to just swap out the turn signal bulb with an LED bulb, but your blinker may blink fast because of the low power consumption of LEDs. The fix for this is very simple. You will need to buy a resistor and connect in in the wireing of your tail lights. It does require a small bit of splicing wires, but this is not a big deal and I will be happy to help you with pictures or whatever you need since I am planning on doing this mod as well.

You will need a resistor for each tail light (right and left). Here is a link to what I am talking about.
Product Listing - CAR I believe it is the 4th one down the list on this page.
Let me know what you find and if there is anything else I can help you with. Once I do this mod on my Highlander, I will take pictures and put together a "how to" I am hoping to do this within the next month or so. I am still trying to decide if I want to do this OR just buy the Hybrid LED tail lights.
Keep in touch!
2005 TOYOTA Highlander
Low beam headlamp
9006
9006SU Silverstar ULTRA for Ultra Night Vision - The Whitest and Brightest Halogen
9006ST Silverstar High Performance Lighting: The Whiter and Brighter Halogen
9006XV XtraVision Halogen Upgrade: Up to 20% Brighter
9006CB Cool Blue Halogen Upgrade: White Hot; Super Cool; 100% Street Legal
9006LL Long Life Halogen Upgrade: Lasts one and a half times longer
High beam headlamp
9005
9005SU Silverstar ULTRA for Ultra Night Vision - The Whitest and Brightest Halogen
9005ST Silverstar High Performance Lighting: The Whiter and Brighter Halogen
9005XV XtraVision Halogen Upgrade: Up to 20% Brighter
9005CB Cool Blue Halogen Upgrade: White Hot; Super Cool; 100% Street Legal
Parking light
7528
Front turn signal
7528
Rear turn signal
992 (7440A)
Tail light
7443
Stop light
7443
High mount stop light
921
921LL Long Life Upgrade: Up to twice the life of the standard lamp
Fog/Driving light
9006
9006SU Silverstar ULTRA for Ultra Night Vision - The Whitest and Brightest Halogen
9006ST Silverstar High Performance Lighting: The Whiter and Brighter Halogen
9006XV XtraVision Halogen Upgrade: Up to 20% Brighter
9006CB Cool Blue Halogen Upgrade: White Hot; Super Cool; 100% Street Legal
9006LL Long Life Halogen Upgrade: Lasts one and a half times longer
License plate
168
Back up light
7440
Front sidemarker
7528
Rear sidemarker
168
Glove box
74
Map light
168
Dome light
DE3175
Step/Courtesy light
168