I have 3 MSD 6A's installed on the car which was not a easy task to install and mount. That is why you see it mounted creatively where it is now. The RX-7 Engine bay is not the most user friendly place to mount things. You have to get quite creative in order to make things fit. This where the size of my Stock Mount intercooler and Intake box came in handy. If you read the section about my spark plugs then you will already know I had a hesitation problem at High RPM. The RX-7 ran sweet with the new plugs installed. After traveling all over California to race I did not want to have a ignition problem again. So I decided to install 3 MSD's. It might be a little over kill, but it gives me a peace of mind. Performance wise, the MSD made more of a Mental/Reliability increase than anything. I am not sure if it helped me go faster or not.
Above are picture of the MSD installed in between the Intake System and Intercooler. Also a pictures of the wiring I did with molex connectors. Pretty cool huh?