The Creek doesn't match the Prelude II impedance curve, as your listening proves. If you'd rather keep the Creek, then a speaker with a flat impedance curve will match better. I'm not sure the Totem qualifies.
Here is an integrated amp that doubles power into 4 ohms. There are many others, I'm sure. Portal Panache. It's available with a home trial, so you could demo it with your speakers to hear for an improvement. I'm not endorsing this amp, just highlighting it for you. There are comments in the threads about it.
The Classe CAP-151 and Audio Refinement Complete come close to doubling power into 4 ohms, though they don't quite get there. They do get closer than the Creek, however.
Here is an integrated amp that doubles power into 4 ohms. There are many others, I'm sure. Portal Panache. It's available with a home trial, so you could demo it with your speakers to hear for an improvement. I'm not endorsing this amp, just highlighting it for you. There are comments in the threads about it.
The Classe CAP-151 and Audio Refinement Complete come close to doubling power into 4 ohms, though they don't quite get there. They do get closer than the Creek, however.