As others have said, before you spend a lot of time and money buying new gear, spend some time working with the SansAmp. You can easily get a very clean and articulate P-bass sound with the SansAmp by keeping the blend down and judicious use of the bass control. Also, you have a mid control on the V2. Don't be afraid to adjust the mids to get some articulation. Perhaps turn of the Speaker Simulation, as well.
A compressor can help if you know how to set it up, but it can also completely muddy up your sound if you don't set it up right. The HX Stomp is really great, but there's so many options and it's very easy to get a really poor sound from it unless you know how to work with each model and how to set it up to achieve the tonal goal you've set.
Another often over-looked aspect is your plucking technique. That alone can be the difference from mellow and muddy to in-your-face aggression. Perhaps you need to spend some time making sure that you're getting the most from your technique.
A compressor can help if you know how to set it up, but it can also completely muddy up your sound if you don't set it up right. The HX Stomp is really great, but there's so many options and it's very easy to get a really poor sound from it unless you know how to work with each model and how to set it up to achieve the tonal goal you've set.
Another often over-looked aspect is your plucking technique. That alone can be the difference from mellow and muddy to in-your-face aggression. Perhaps you need to spend some time making sure that you're getting the most from your technique.