Context: After buying my IS350, I only had one smart key. In my attempt to obtain a second key, I've managed to stumble into several obstacles, and I noticed there isn't one central repository for this knowledge here on CL.
I'll add more information as it comes into my memory.
From Sewell (all prices include CL discount):
Smart Card Key: $250.51
Key Fob (does not come with master key): $127.50
Master Key: $53.87 (uncut), $54.73 (cut with VIN)
Smart Cards: ~$200
Key Fobs (most eBay key fobs are programmed, and in NEW CONDITION only): From $20 - $80
Master Key (Uncut key blade): ~$10.00
Key fobs and key blades are interchangable with 2006 - 2007/2008 - 2011 ES350 keys. Make sure they have the same FCC ID and numeration on the back.
Dealership: Usual charge at around $160 (used key reset), ~$50 - $60 for new keys.
Locksmith: If you find a locksmith with the available computers/tools, they will be able to do both program and key cut for ~$85.00
1. Master Key/Key Blades: these are keys that are cut in coordination with your specific VIN, and therefore would require proof of ownership in dealerships. These MUST be cut with Laser key programs, and can be cut by locksmiths with the necessary hardware.
2. It is MUCH easier to simply add a completely NEW and UN-PROGRAMMED key fob/smart card to your vehicle ECU than to reprogram it for a used key. The process of pairing un-programmed key fobs to the vehicle is fairly straight forward as a add on to the current number of keys associated with the ECU.
2a. The process for adding previously paired/used key fobs and smart cards require a reset of the ECU (16 minute wait per immobilizer reset), along with setting up EACH INDIVIDUAL KEY (including your previously existing keys/original keys) to the vehicle. Furthermore, the ECU would allow a total of 10 resets, before requiring a COMPLETE replacement of the unit - so do so sparingly.
There is a difference between keys and key fobs manufactured for MY 2006 - 2007 and 2008 - 2011.
3a. Keys: The key blades manufactured for MY 2006 - 2007 are two sided, and therefore incompatible with 2008+ vehicles. 2008 - 2011 key blades are cut ONE side only, and the other side is left blank with a pre-existing valley, therefore incompatible with Pre-2008 vehicles.
3b. Key Fobs/Smart Cards:
The 2000 and older lexes cars use a 4 digit code. The 01-07 cars use a five digit code that begins with 4xxxx and the 08+ use a 5 digit code that begins with 8xxxx.
What does that mean for you and me? That means there are Smart Cards that are ONLY compatible with MY2008+ vehicles and ones that are compatible with pre-2008, and certain key fobs only work with MY2008+ vehicles. Other than seeing if the key has already been cut (and if it hasn't, you're relying on the third-party description), there is NO PHYSICAL DIFFERENTIATION between the 2008+ and 2006-07 key fobs. They both have identical FCC ID and frequencies listed.
Here is the interesting part, if you purchase a key from Ebay, or from another member, they may have no idea that there is an inherent design difference in the keys, and therefore may list all keys as being 2006 - 2011.
Please discuss as I am not an expert, and this is my general understanding from my experience.