Dean,

I have my pump in the behind the aft baggage bulkhead along with an Odysee 680 battery. I have another Odysee 680 battery on my firewall and along with a Chelton EFIS system, have a near perfect CG. Originally, I had both batteries mounted on the firewall and due to an extreme forward CG had to re-locate one battery in the back. I am convinced this is the perfect set-up for most Legacies.

Some have the pump behind the seat along with a much larger battery, but I think all-in-all, the dual battery set-up and location I have works best. (with dual 680s)

The only caviat would be if you're planning on a heavy EFIS system like the Garmin 900X, you would need to put both batteries and pump in the rear area to balance the CG well.

Hope this helps,
Don Barnes