This has been the most trouble free car I have owned, you will have no worries on a timing belt because we don't have one, the tC uses a timing chain, and that is a lifetime part. You will need to keep an eye on your coolant levels, the tC engine's water pump isn't as solid as some other Toyota models.
Scion tC carried over last generation engine but added new 6-speed automatic and manual transmissions. From 2005 to 2007, Scion tC had been Scion's most popular model. Scion tC Common Problems & Maintenance Tips