Anyone know a good way to adjust the ignition retard? On my previous car I had an msd ignition programmer and it was a push of the button.... but with the new car not totally sure. Thanks in advance.....

it's all run off the ECM. you'd have to get some sort of piggyback unit and play with that

The tC uses, in conjunction with the VVT-i and ETCS-i, an Electronic Spark Advance system that advances or retards the optimal ignition timing based on signals it receives from these systems. So I'd say manual adjustment of the timing would be near impossible without adjusting the parameters of the whole system.

Repost by you:
http://www.scionlife.com/forums/viewtopic.php?t=60844

Using the E-Manage with an ignition harness added, a support tool, and a laptop, you may be able to do it. This of course is only possible if you know the ECU pinouts for which ignition wires to splice.

I haven't heard of an MSD system to work yet. The new AEM one might work though.