The question is how long are you looking at keeping that bass? If the feel, playabillity, style, unplugged tone, weight, etc. have you convinced that you're sticking to that bass for a fairly long time period (5+ years) then I'd say you can consider some upgrades to bring the instrument up to your desires.
If there's anything about the physical instrument itself that falls short, I'd say that saving that $$ up for an instrument that fits you top-to-bottom is a better bet.
I saved up money from working on a farm for two summers while I was in college to get my bass. I spent a decent chunk of that money on other stuff too fo course, but the goal was that bass. And one benefit of that sort of think time is that I had enough time to be entirely certain of what I wanted. 12 years later, I'm in my 30s and I can't imagine using another bass... this one is my voice.
Now, it's gotten a rather large electronics overhaul 4 years ago, but that was the only place I think my choice fell short, and I knew for a fact that the upgrade dollars were going into a "lifer" instrument.
I'm rambling, I apologize. But definitely consider the length of time you'll be keeping that SX, and prioritize between saving for a new bass vs. upgrades on the SX accordingly.