$110 per assembly.... that's actually cheap! I have seen them as high as $180 a piece for a 300SD.
If you are going with oversized, expect to pay a little more. This is not a bad price IMHO for oversized piston assemblies with rings.
Be sure you can use the oversized pistons... it may not be adviseable in your car. You may need to re-sleeve and stay with standard size. This may be cheaper in the long-run considering $440 for pistons.
Just my $.02