Getting good pickups is one of the best ways to improve the tone of any bass. I installed Delano pickups in two of my basses with excellent results. I wired them passive with volume, blend, and tone controls. Very low noise, hot passive vintage tone, and very dynamic. I also highly recommend Nordstrand pickups - I put Big Splits in my Lakland - but I don't know if they make them in P/J configuration like your EBM 5.
"The best tone comes from practice!" - Lakland 5 str w Nordstrand Big Splits - Carvin Kit 4 str fretless w Delano P/U - Eden Time Traveler