Depth isn't any different really, the width will be the same but the advantage of a tourer comes when loading with the extra height and you can fill it up to the height of the roof, where as the saloon only has space up to the boot.
Personally I'd never have another saloon simply because of all the extra space you get with a tourer.
And the glass opens so you can fill the boot, then cram those last bits in through the window
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How to view a car - everything you need to help you inspect a used car
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