Swapping ETMs require a dealer download, so your ETMs on the shelf will no longer work. The yellow one is the newer version.

Klaus
--
Always willing to listen, just not able to take direction.

hello,
yellow label means the throttle was replaced at some point.
you cannot swap throttle bodies, every etm is paired (electronically) to the computer.
if you do swap throttles, Volvo will need to upgrade the software so that it will function properly.
cleaning the throttle can cause more problems than it may solve. personally, I notice hesitation when my 99 is cold, and sometimes the idle acts funny, but until it starts limping, I won't touch the throttle.
for the money, xemodex is worth it if it becomes unbearable.
good luck.
--
Jake