2 250watt for a 55g? Thats a lot of wattage for a tank that size.
I only have 1 in my 55 and it maintains a constant 80F and I'm from the East coast where its in the 30's right now.
You might want to remove one of the heaters otherwise it may "boil" your fish.
All you really need is about 4-5watt per gallon and a single 250watt is right on the mark for a 55g.
Also, you're right the Stealth's are sweet..got 2-250's in my 125g tank..and it mainitains a 80F...plus it matches my black background.