Hey Mike, my name is Juan Saavedra and welcome to the hobby.
The other guys are right about the
P. dovii in that they are killers when they get larger and they'll need a separate tank, so now might not be the time to get a large
P. dovii. Also it might get boring after a while if you don't have a full appreciation of the species that can be gained from... READ BELOW
I got my first Dovii 20 years ago at "1 and found that he did really well in a community tank with other Central American cichlids his size, i.e Jack Dempsey's, Fire Mouth cichlids, A. labiatus, Convict cichlids, etc.. and that was in a 30 gallon tank. Can you believe it!?!
With a 150-180g tank I'd suggest to have fun with it. Decide what kind of substrate you want ( gravel or sand), then go to a garden center and pick out some cool stones, large and small. Make caves with your stones and pile your gravel (or sand) over it and when the cichlids start moving the gravel/sand they'll start discovering their new territories. They'll fight over their territories and mate in them or get kicked out and then get them after a small skirmish. Get plastic plants and long-strip air diffusers to make it look beautiful. Also make sure you get a light and top(a given I guess) filters too.
Your new to cichlids right? Then I'd suggest to get small fish, I mean, like 1 inch. And get as many as you want 30... 40... haha that's kind of pushing it a little, but you get my point buy, buy , buy you have a huge tank! Get some Convicts, Salvini's, Green Terrors( a SA cichlid), the dovii you wanted, managuense, motaguense, carpintis, loiselli, Fire Mouths etc...
When you have a tank with a lot of aggressive Central American cichlids and they are raised as young together they tend to coexist well when they become adults.
This kind of start teaches you the behaviors of each species and why you like or prefer this species over that species. It'll also allows you to see growth over time as your fish mature into beautiful adults.
Fish are going to die! Trust me, it happens to the best of us, but remeber this period in your involvement with the hobby is the growth and learning stage so its a time to explore and have fun.
Don't let other peoples opinions of how things are "supposed to be" deter you from exploring.
If you want African cichlids with your Central Americans or South Americans, go for it man! Then as you start developing a passion/ addiction for the fish you'll migrate into more specialized areas of the hobby.
You might become the specialist or go to guy of a certain species that you've learned to love and appreciate and only keep that fish. You might decide that you like African's and not Central Americans ( not African people and Central American people, but the fish of course) and only keep Africans from Lake Tanganyika have tanks dedicated for specimens from a certain location (i.e." Kitumba"). You might decide that you like Dawrf cichlid's and only keep them. You might like all cichlids which is what ends up happening to a lot of us and have a little of this and that in their own separate tanks by continent or not. You might end up liking hybrid cichlids like the show discus or flowerhorns and you'll develop a lot of enemies for doing so. More so on the flowerhorn side of things not show hybrid-discus which of course they don't call them hybrids but they are.
Sorry for that, if you didn't notice I was having a moment there cause love my hybrids and the American Cichlid Association rejects hybrids and I am hurt that after 20 years of being in the hobby there is no place for people like me that are so passionate about the cichlids as they are. By the way I love pure fish cichlids as well.
Lastly, you might become a breeder who has no gravel in his tanks just water, fish and sponges filters all in a heated room where you will definitely sweat and be wiping the sweat off of your eyebrows and forehead and you'll be blind if you where glasses haha. And don't underestimate someone's setup just because it isn't pretty these tend to be the people who become legendary in the hobby. Now, of course, you can be a breeder and have a beautiful setup, but usually breeders spend there attention on beautifying a strain of fish and not necessarily their tanks.
So there you have it! Have fun, learn and get out to support your local pet stores, explore fish on Youtube and the different forums, become a member of your local fish club and enjoy God's beautiful creation - the Cichlid.
Nice retail sites for Central American cichlids
My hero in the hobby a true legend Don Conkel:
http://www.donconkels tropicals.com
Next, Jeff Rapps also legendary and has great fish:
http://www.tangledupincichlids.com
Lastly, Dan from Florida is what I call him:
http://www.cichlidsoftheamericas.com
Also, Aquabid.com come it huge! I don't know about everyone else but I visit
http://www.aquabid.com just about every time I get online.