I do not have a "sump bump" to clear the exhaust header.  There is a good 4-5" of clearance at the bottom and rear of the tire well to the exhaust.  My tire well is identical to the well in your red body picture above.  The only indention is to clear the shock tower.  Folks used to mount the spare tire bracket on that indention.  There is a picture of the spare tire mount and the hold down bolt on the Manx Accessory board display in the above pictures.   If you can see my album there is a picture of the spare tire battery wells on my buggy.

I have never seen a "sump bump"for an exhaust on any Manx body with a tire well.  If there is a picture of one please post it.   I'm now curious.