Hello i have was wondering something about the head shims of ur nitro engine. I looked at the website of the engine i have and it says it could go up all the way to 16% nitro without modification. The thing is i am running 20% nitro and it says for every 5% more nitro content u use u have to add a 0.1mm shim under the head. will this 4% more content affect the engine in a bad way if i dun put the shim on? BTW it has flat head screws holding the head down which will be a pain to remove. NOt to mebtion some bent screwdrivers.