The Saito 115 is lighter and smaller than the YS (great engine also) and gives as much if not more power. I converted my old GB 300 by removing the OS1.08 and installing a Saito 100. That amount of power is perfect for me. I dropped the weight down 17 ounces.

Pull pull on rudder is great. I used the belcrank system from Central Hobbies to give me two outputs to the elevators. It's mounted about 6-8" forward of the tailpost and is driven by a pushrod from one servo mounted forward on the supplied servo tray. This keeps the weight of two servos off the tail. A bit pricey but it's ball bearings and is really quality.

Some people have trouble with the light and fragile ribs and LE sheeting. That is part of the design and very necessary to get the wing light. The lighter the wing the quicker response time in roll. That is it will stop nearly instantly once ailerons are neutralized.

Legality aside plans can be copied at Kinkos. I'll bet some kit cutter would do a short kit.

I bought two more 300 kits this year off eJunk. I NEVER want to be without the GB300 in my fleet. The best aerobatic model I've ever owned. Also it's the first airplane I'll fly after an absence and rusty thumbs. Soooo easy to land.