You will need to go geared to get decent slow speed performance. Also speed 400 is too big for indoors.
Several sorts of planes may suit.
(i) I found a kit for a speed 400 aerobat at my LHS - and boy, it turned out to be very fast and very small. Damaged it quite badly until I got the rates sorted, but it still scares me :-) That was direct drive speed
400. flies in the 30-50mph range and lands about 20-25. I stuck in the bits for a trashed Picojet, and it flies - better than I do :-) Only aileron/elevator tho.(ii) Multiplex Picojet Combat. Comes with 480 motpr, but your speed control and packs are ideal. Faster than a zagi and more fun. Slightly less breakable.
(iii) gear theh thung down 2.33:1 and stick an 8x6 prop on it, and find something - maybe from mountain models - that is light with LOTS of wing area. OK, they won';t do 3D on that motor, but plenty of scope for most aerobatics.
(iv) Go vintage, and build a big old lightweight slo plane. Ther are lots of kits out there for 40" 20 oz high wing floaters that will drift around calmly after the wind dies down.
Rally it depends on whether you want to build or just fly. If teh latter, ou will end up with a collection of motors since most of these come with the motor. However they ae cheap, and may be sold in job lots on EBAY or saved up for that multi-engined bomber one day :-)