Hold on a minute before you get them...
Blue/common/gold/german rams are all the same species and would be fine in your set-up though, if they were to pair up, they'd harass the cories to no end while breeding unless you could fit in a larger group of cories + increase the number of hiding places for them. You don't realy have room for mroe cories if you add the rams so just add some mroe hiding places and I'd expect them to be ok.
Bolivian 'rams' (which aren't actualy rams so to speak) are a little more aggressive, more territorial and would cause somewhat more trouble to your very peaceful fish if they were to pair up and breed. They are, however, a lot hardier and I preffer them to the other rams because they are less artificial in their behaviour - more like cichlids and les inbred - and I think they have more character. I would not suggest them for your tank though.
In reality, though the rams are ok, I would not reccomend any cichlids for your tank - simply because you already have mid-to-lower level fish. Try a pair if you are set on them though. If you're still open to suggestions, perhaps a trio of honey gouramies (colisa chuna/sota) are something you'd be interested in. Alternatively, check out colisa fasciata and colsia labiosa. If you like them, either would work if you keep a lone male or two or you could just about manage one of each if you also provide plenty of cover - particularly floating plants or tall plants.
I have had numerous contradicting advice from LFS and the Web so was wondering if anyone has had personel experience with these fish. Any advice appreciated 
