My other car is a MINI!!!!
it's not about the internal diameter mate, LCR brakes will go under just about any 17's in that respect.
it's about the width clearence. high offset wheels like yours won't have a chance of fitting unless you're running big PCD adaptors. Mercs are 5x112 so I'm guessing you'll have 20-25mm adaptors, in which case they might fit.
Best thing to do would be find someone local and friendly with LCR brakes and try a wheel from your car on theirs to see if it clears.
saves you spending money on something that MIGHT not fit.