How complex can we make things?

I would like to make protein models using this system. However, before I purchase the system, I need to know, would it be capable of doing so? I have attached one of the simpler models.

I would give that an emphatic NO!

Without the use of support material all overhangs should be less than 45º.

There are reprappers working on enabling support material by using two print heads.
I would guess that within the year dual head bitsfrombytes RepMan machines will be able to print such models but as of this moment only commercial FDM machines can accomplish this task.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Alright, thanks for the quick response.