Just a thought... If you are buying a Sport 10.1, the work of installing it is actually not huge. You could do some of the work in chunks, saving a chunk for a rainy day, then another for the next rainy day. That would avoid the down-time that none of us want in the summer months. The Sport installation is really quite easy.
Suggested "chunks" to consider as pre-work for that one day when you actually install the unit:
1) magnetometer... physically mount it and run its three wires in a single bundle up to the cockpit area, coil and stow enough length of wire to go to the EFIS connector position with plenty of service loop or terminate it in a simple DB9 connector in a handy place so wires from the EFIS connector can be run to a mating DB9
2) prep the EFIS itself by sourcing and installing pitot-static connectors - get the connectors and tubing needed to Tee into your existing pitot-static lines and be ready to go for the pneumatic portion of the install
3) if your panel is a group of sub-panels, source a new sub-panel, mark it, cut it and install EFIS mounting hardware as well as mounts for whatever else needs to go in that sub panel. In short, be ready to make it a "bolt on" installation
4) pre-wire the EFIS connector to the greatest extent possible with power, ground, RS232 wires brought out in a bundle... this is where you might find it easier to run the magnetometer wires out from the EFIS connector and into a DB9 disconnect located perhaps over on one cockpit sidewall
5) plan and acquire the necessary power and ground connection hardware. If you're installing a new CB for the EFIS then you might even be able to have that CB hanging off the end of the EFIS wire bundle, ready to insert into a new hole in the panel - just connect to the aircraft power and you're ready to go
I installed a Sport EX this past summer and had to do fairly major surgery to make it happen but I followed something similar to the plan outlined above. Once I had the metal work done I found the labour content for the rest of the installation to be fairly minimal.
(I'm kind of jealous that you have enough real estate for a Sport 10.1 - I didn't. The new glass in the GRT screens is fantastic - you'll love flying behind it!)