My experience has been that turntables require appropriately high quality phono stage to sound their best. While I have not heard the Darlington Labs MP-7 phono preamp, I have doubts that it would be up to the sound quality of your intended new turntable. My general rule of thumb is a very carefully chosen phono stage in the same cost range as the turntable. Whenever over the last five decades of me violating this I later found the Phonostage was significantly compromising the sound quality of my turntable.
There are many excellent used high end phono stages on the market.