There is enough processing power in the player to do some of the things you describe.
However, you would need to write the software yourself, or convince someone to write the software to do it, as it doesn't run DirectX, doesn't use an Intel processor or Windows, and therefore can't use those plugins.
Certain digital signal processing features have already been added to the player. Examples are real-time dynamic compression/volume leveling, Left/Right soundstage image placement, and, in the latest beta, stereo bleed. Some of these are found in the default player software, and others can be found in third-party addons such as the Hijack kernel.
Note that these features are present because they have a direct benefit to the player's primary purpose: To be a high quality car stereo. Other features, such as adding echo, removing vocals, or pitch shifting, while they are interesting novelties, aren't related to the player's core function and probably won't appear in the default software.
If you wish for any of these novelty features to be added, you can take a look at the source code for Hijack and see if it's possible to insert them yourself. Mark is often happy to add features to Hijack if he's supplied a nice clean ready-made patch.