Pre Amp or Amp Best Money Spent

Hello, putting together my first system around a pair of non sig. Vandy 2ce's late serial numbers. I am looking at Rogue tube pre/amps. I am wondering if I should spend the money on M-120's with an entry Rogue preamp or go for the Rogue 90 with Rogue 99 pre? Obviously there are tradeoffs but where is the long term benefits. I will be buying used. Thanks Dean