Update! I replaced the throttle body with the mercedes 113 141 0125 74mm. Got a used one with 75k miles on it at a junkyard using car-part.com. Ended up being $40 for the throttle body and $20 shipping. I purchased and used http://www.ebay.com/itm/Mercedes-Benz-W202-W203-W204-NEW-GENUINE-Throttle-Housing-O-Ring-305-997-03-45-/151161574603?pt=Motors_Car_Truck_Parts_Accessories&hash=item2331ee94cb&vxp=mtr o-ring for $11.49 with free shipping. And I also upgraded the MAF to http://www.ebay.com/itm/98-10-MERCEDES-MASS-AIR-FLOW-SENSOR-METER-MAF-S500-S430-1130940048-0280217810-/300854699060?pt=Motors_Car_Truck_Parts_Accessories&hash=item460c566434&vxp=mtr 74mm one, which was $20.99 free shipping.

This appears to have fixed my issue. I have not had the P0123 code came back yet, and I no longer experience the delayed accelerate symptom. If you have stumbled across this thread and are looking to perform the 74mm upgrade, please take note that if you purchase the 74mm MAF housing you will need to take the sensor off of your old OEM MAF housing and use it on your new.

Thank you to all of the forum members who helped me in this thread last month!