Attention: TDR Forum Junkies 
I don't know if you know what a pallet slip-sheet is, but they make awesome cold weather radiator restrictors. Every warehouse worker, forklift, or truck driver knows what I'm talking about. Better yet, you can cut a flap in the middle and adjust how much cold air reaches your radiator by folding it all the way or part way open or leaving it closed when you slide it in. They are entirely waterproof thin sheets of very tough flexible plastic (thinner than cardboard) that can be cut and trimmed with scissors to slide very nicely between your radiator and intercooler (which you don't want to restrict air flow through like external, grill-mounted winter fronts do).
I leave an extra few inches sticking out at the top to make it easy to grab onto & remove when not needed. Just fold it over. Popping the hood takes longer than sliding it in or out. In the off-season, it rolls up very compactly and stores in my toolbox. Get some extras and keep a full sheet (about 4' square) rolled up & stored in your truck for those times when you need to slide underneath it without benefit of a creeper - they're very tough and slippery and slide nicely on dirt, mud, gravel, snow, cement, or whatever. I keep a large heavy plastic semi mudflap at home for doing similar driveway repairs/inspections.
I leave an extra few inches sticking out at the top to make it easy to grab onto & remove when not needed. Just fold it over. Popping the hood takes longer than sliding it in or out. In the off-season, it rolls up very compactly and stores in my toolbox. Get some extras and keep a full sheet (about 4' square) rolled up & stored in your truck for those times when you need to slide underneath it without benefit of a creeper - they're very tough and slippery and slide nicely on dirt, mud, gravel, snow, cement, or whatever. I keep a large heavy plastic semi mudflap at home for doing similar driveway repairs/inspections.
