Meth has significant effects on serotonin (even though those are secondary effects to its stimulation of dopamine receptors), which right away makes it a bad idea considering tramadol's SNRI qualities. Subjective effects of tramadol are usually stimulating in their own right (thanks, again, to the inhibition of serotonin and norepinephrine), which can be an uncomfortable feeling when combined with the granddaddy of all stims. As already mentioned, both drugs can reduce the seizure threshold.
So, yeah, a bad idea all around. I would be remiss if I didn't mention that I've tried this combo before; I took 100 mg of tramadol at the tail end of an oral dose of meth in an attempt to combat the comedown, and I lived through the experience. However, just saying that I was ok is an example of the non-event feedback loop; basically, if nothing bad happens, people assume it's ok to repeat. This is not the case; you might be fine, but the odds are against you as per the aforementioned points. Steer clear.