Yeah don't start with more than 2 of them. Be aware that tramadol lowers the seizure threshold, in short it causes you to have seizures easier. People with no history of seizures can have seizures on this drug.
Also be aware that the effects from multiple doses might stack in a 1+1=2 1/2 kind of way. Don't assume a higher dose will get you higher, it might just make you feel very sick.