No harsh comedown experienced whatsoever, at least not in our group. Euphoria typically lasts for 2.5-4 hours, gradually fading away leaving behind some residual stimulance. Don't expect to sleep the first 8+ hours after intake, but if you keep your total intake below 160-180 mg, sleeping won't be a problem once you come down.
also i'd probably end up comboing it with at least md, maybe some 2cs, would this be a) dangerous or b) fucking awesome?
I would not advice combo with MDMA (or isn't that what you mean with md?), too much dopamine release imo. If you decide to try this combo, I would suggest you wait with dropping MDMA about 3 hours after taking in the 4-FMP. This way the redisual stimulation after 4-FMP euphoria has worn off will be supplemented with the huge euphoria caused by MDMA. So essentially you'll have a 4 hour build-up to your final rush of chemical happiness, and you won't end up with that much of risidual stimulation (which can be shitty once the magic is gone).
Combination of 2C-I and 4-FMP is one of the best ideas ever. Not only does it feel like regular rolling most of the time, 4-FMP also seems to enhance the visuals. For more and deeper visuals, you could add some 2C-E to the mix (so 2C-E + 2C-I + 4-FMP). Combinations of 4-FMP with 4-AcO-DiPT can also be truly mindblowing, 2C-D is also a good one. Haven't really got much to say about the other phenethylamines, I suggest you watch out with 2C-T-7 and the other ones, well...they just don't seem as much win as 2C-I/E and 4-AcO-DiPT.

I have actually done some (non-academical) research on the different combinations with 4-FMP and 2C's, so feel free to send me a message if you want some info on the appropriate dosage.
ffs, treacle was actually asking where the research is. i.e. requesting information on how to better understand it
Perhaps I misunderstood, but this was not how I understood his post. First of all, this is the 4-FMP thread so it's not the place to debate on the neurotoxicity of MDMA. Secondly, a genuine information request typically consists of more than two sentences and is a reaction to a statement; my statement was not really about MDMA but about the combination of MDAI + 4-FMP. And thirdly (which is my own fault so no excuse) I am absolutely fed up with people quoting the 'cognitive impairment study' as the holy grail of MDMA research. I have personally put down at least 5 arguments that question this study, all ignored by the people claiming MDMA is non-neurotoxic.