According to the temple of V-Tech artice here is the summary of changes.
http://www.vtec.net/news/news-item?news_item_id=384913

Since its groundbreaking redesign in 2004, the Acura TL has solidified its place as both the top selling Acura and best-selling luxury sedan in the country. The TL comes equipped with a 3.2-liter, VTEC V-6 engine, a drive-by-wire throttle system, and an available close-ratio 6-speed manual transmission with limited slip differential. For 2006, a Tire Pressure Monitoring System is added to the TL’s already long list of standard safety features as are two new exterior colors.

Tire Pressure Monitoring System (TPMS)
Revised engine management system and steering angle sensor logic help reduce torque steer
New Colors:
Royal Blue Pearl replaces Abyss Blue Pearl
Alabaster Silver Metallic replaces Satin Silver Metallic
Deep Green Pearl discontinued
New horsepower/torque ratings: 258 horsepower SAE net (Rev 8/04) at 6200 rpm, 233 lbs-ft. of torque SAE net (Rev 8/04) at 5000 rpm

 

This one is gonna get locked as this info is already available in a different thread...

 

well the tire pressure monitoring system is required by law now...so it was a given

 

https://acurazine.com/forums/showthread.php?p=1255234
Normally we would merge this with the 2006 thread, but this one just gets a since it is already there.