You already have the engine so the next step is clearly the Ultra Stick 40.

A lot of fun and cheap. (you have everything except the plane which is around $129.00)

Then I would save for my third plane, Hangar 9 Pulse sounds really great with the OS AX 75 option which can handle a 14"x 6" prop at 9500 rpm. with cheap 15% nitro fuel.

If you want to go further then acquire a Saito 100 and bolt it to the Pulse and have a great time.

Just my opinion.