Tunze powerheads or convert to Wavebox 6215?

[SanguinesDream]

So, I've about had it with the korelia powerheads in my 125 gallon. No matter how I position them, I have dead spots. I even modded them for greater intake. Better but not good enough. The Tunze choir has got me singing and I am looking at replacing the korelias........now, do I replace all four or do I go for the Tunze Wavebox 6215?

Tank is 125 gallon, 5'long x 18"wide x 26" high. What say you?