Personally I would go with 2x 250W. I have 2x 200W Stealths and they barely keep up with my 90g (which is actually about 100g of water when you count the 20g
sump). When one failed the other day (my fault...let a sump compartment get too low so it turned itself off...worked fine once I added water) my temp plummeted from 78 to 64 degrees Fahrenheit and was still going...thank goodness I happened to glance at my thermometer or I could have a rather empty tank :s.
The Stealths are great though...I love 'em
Good luck
