Well luckily I had all the live rock in an old tank so I didn't have to fork out for that. But as a whole the tank is very easy, Ive added a Eheim Pro 2 Filter which I bought second hand from my work for £15. I would say, adding an external is a must.
Ive kept the internal filter, and filled it with chemical filtration, but it also adds abit of circulation to the tank. My pump in the internal filter broke a couple of weeks ago, so I bought the 1000lph version, which fits into the same fittings so that was a cheeky bonus.
A Prizm protein Skimmer which is poor, but is needed, which fits on quite nicely but cutting into the hood flaps.
I also upgraded the lights using an Arcadia I-Bar, which I don't know If your Vision 180 came with the T5's but you will them if you are trying to grow corals.
Ive also added a powerhead for abit more circulation.
So all in all, if you have the stuff handy or know someone who is selling the parts quite cheap, its an easy job.
But it can become quite costly if you are starting from scratch.