Different basses are just different. It's impossible for a Stingray, even a real one, to sound as good or better than your Spector if the Spector has the sound your ears are wanting to hear from a bass right now. Just because the Stingray is this beloved, iconic model doesn't mean it's going to offer any improvement over something you already like a lot. Nor will it contain the things you enjoy about another bass. You have to listen to the classic Stingray recordings and get into that sound on its own terms. What I will say is that Stingrays are not necessarily the most deep and smooth sounding basses, but they are audible. That's their main strength besides looking cool and neck stability. They don't have that Spector scooped hugeness to the sound, and they don't sound great in isolation, but they are easy to hear in a loud band and don't bottom out if you play hard. They keep hitting harder the harder you play. So, they have their practical merits and are very functional tools in a band. I find I can help control the tempo better with a Stingray because it hits like a kick drum and you can reign everyone in if need be. But it'll never sound like a Spector and no amount of pickup swaps or money spent can change that. Even a USA EBMM will let you down if that's your goal.