Is turning a guitar down bad for the neck?

I usually play my Fender Strat in drop D, but i have been wanting to play in drop C with the other strings one step down. Is this going to warp the neck? Will i need to get a neck adjustment? I have another guitar that i keep in drop C, but I just bought a Seymour Duncan Invader pickup for my Fender and i want to see how well it sounds in drop C.