If I were you I would approach this as logically as possible. Let me discuss preamps in general for a moment and you will see what I mean.
What exactly does a preamp do? It simply raises the level of a microphone signal. This is because many mics put out a signal that is too weak for the rest of the system to process efficiently and effectively. Thus, the proper way to use a preamp is to only raise the input gain as much as is needed to achieve adequate meter strength or recording volume. When you do boost the level of a preamp, the circuitry itself adds distortion and in worst cases, some hiss. This is what is referred to as coloration and some people feel it is a good thing and some feel it is a bad thing. You must decide this based upon what is being recorded. Some manufacturers use this coloration as a selling point.
Now on to your predicament. If your drums are loud like mine, then you won't need to turn up the preamp gain very much
if any. Many of the drum tracks I have recorded have been so loud that the preamp was almost peaking/clipping with no gain at all, (preamp volume all the way down.) In fact, I have inserted inline pads to keep the level under control. OK, I have turned up the overheads, but the toms, snare, and kick were usually peaking when close mic'ed.
When you do not turn up the preamp gain it is almost the same as being set to bypass. For the most part the preamp simply passes the signal through unchanged. (...And, I might add, adds little or no coloration.) For this reason I use a cheapo Behringer ADA8000 8 channel pre for my drums and I get good results. They sound alive because I use decent mics and I have treated my room to improve the sound.
My point is that I would not spend big money on something that won't be doing much for you. I would shop for a good preamp for vocals, stringed instruments, and other quiet sources, but not for power drums. I do have more expensive preamps and I cannot tell any difference when recording drum tracks. I believe you only hear the difference between preamps when you need to turn them way up. That is when the good ones shine through and show their true colors.
Hope this helps.
