Assuming you have some sort of budget in mind. Okay. So here's what you do. Take that budget, add to it whatever you think you can get for your amp, and the power cord attached to the amp, and the interconnect running to it, and add all that to your budget. Then you go out and listen to what that amount of money will get you in a good integrated. If its not a helluva lot better than what you can get with a better preamp, then get the better preamp.
But I will be shocked if that is the case.
But I will be shocked if that is the case.