Now then, Ive come to the conclusion I want to fit my heat shield now. But there are these weird screw in things that get in the way. 2 situated on the heat shield for the exhaust manifold and the other 2 nearer the front. the front 2 can stay as they're not in the way! (it's where the engine cover originally pushes and clips into and has a rubber bushing on top. What's the best way to take these out? Ive tried big pliers etc, but I don't want to ruin them anymore than I have as I may want to return to stock at some point. I know they simply unscrew, but is there a tool for the job?