The usual stuff to get when you go for a tach is the harness that leads to the small clock and take the clock and the three rubber wedges and the face plate for the clock too. Tell the JY guy you'll bring back your big clock to install in place of the tach. The seat heater breaks inside the seat where the wire connects to a thermostat. EZ fix there. The bosch stuff under the seats are airbag crash sensor and abs controllers left and right respectively. See if you can find a junkyard where the prices are posted up front and not dickered after you've pulled the parts.