RE: gst horsepower
No, it's nowhere near. Even stock 26cc gas engines don't develop 5hp.
You must always take horsepower quotes on nitro engines with a pinch of salt, as the result is highly dependant on how the test is performed and almost any result you want can be obtained through tailoring the test toward the result. They're not lies, they're just subjective. HP sells engines, torque wins races. Take this for an example...
Company 1 makes a .21 size engine which develops 2hp at 21,000rpm and 0.8hp at 35,000rpm.
Company 2 makes a .21 size engine which develops 1.5hp at 21,000rpm, and 1.2hp at 35,000rpm.
Which engine is better? Company 2. Which make will quote the higher horsepower? Company 1. See why this is largely irrelevant? The difference between a cheap and an expensive engine is how the powerband develops as the revs increase. Hope that helps with your future investigations.