Another Timing Question

Did my tuneup 2 weeks ago. During the process, I advanced my timing based on what I'd read on here. Car was set at 10 degrees; I read on here recommendations to advance it to 12, as well as some comments that people had advanced even farther. I wound up advancing to 14 degrees. It's been running great, and I haven't noticed any adverse effects, but thought I'd double check with the experts--what does too much advance act like?

For further info, I'm running a stock cam and heads, but have an MSD 6AL box and MSD coil.

Should I leave it as is, or back it down to 12?

Thanks,
Greg