DO NOT take 100mg of 2C-E. LSD, because of its properties and its incredibly tiny dose, is one of the world's most physically safe substances. You could take hundreds and hundreds of doses (although I can't see that being a good idea mentally) and be alright physically.
2C-E on the other hand is an entirely different class of molecule with entirely different effects and a much, much higher dose. It raises heart rate and blood pressure as it begins to get very strong, and as egor mentioned, as you raise the dose it gets exponentially stronger very quickly. LSD, on the other hand, has a linear dose-response curve; that is, if you eat 3 times as much, you'll get approximately 3 times higher. If you eat 3 times as much 2C-E, though, the intensity will be incredibly higher, much, much, much, much more than 3 times.
Please don't try taking an insane dose of 2C-E. If you find yourself wanting to work up, work up by 1-2mgs each trip, because even that much will make a big difference. If you decide to just go and double your dose, you could be a really big trouble. And I don't know for sure, but I would not be at all surprised if 100mg of 2C-E would kill you or at least cause a lot of damage.
Just don't do it, man. If you get hurt or die, it'll give them a reason to emergency schedule 2C-E, and we'll all come find you and destroy you for reckless endangerment of the cause.
Oh, and this belongs in the B&D 2C-E thread, so I've merged it in.