Hi,
Here is a very popular library to handle Dynamixel motors, capable of receiving data at 1Mb/s.
It is based on Arbotix software, which uses its own serial ISR and not the one included in HardwareSerial.cpp
http://www.pablogindel.com/2010/01/biblioteca-de-arduino-para-ax-12/
My question is whether, as Mike says, disabling timer0 interrupt effectively affects serial reception; I think it don't, because while the CPU is handling an interrupt it blocks any other interrupt, am I right?
Pablo.