Is it possible to interface your basic stamp to the tuner serial port instead (inverted TTL) and have it feed this port psuedo-sony stalk packets instead of basic serial commands.

Sounds doable.. there's 2 +-12v pins on the basic stamp that are for normal serial, all the other 16 pins are 0-5 or possibly +-5. I'm not sure that it's entirely as flexible, I'm going to use some of the extra buttons I made to launch apps or toggle what's shown on the screen. Maybe stalk inputs could be ir_translated to fake codes that another application could intercept to do the same thing, that sounds reasonable enough.

This should prevent delayed controller commands and also completely free up the serial port for other uses.

I'm confident the delay can be solved by tweaking the priority, just haven't looked into it yet. I also have a display to drive, so it doesn't save a port unless you use the tuner's serial port for that too; that would be good for the k610a (it's TTL-level anyway), but I don't know if the 7000 or 9000-series (that use full +-12) will work.

Since the empeg is remotely mounted anyway the tuner isn't needed (in most cases).

If you had one before you probably still want it if you're moving the empeg to the trunk..