Your grandpa's plain-Jane W221 Mercedes-Benz S600 is his pride and joy. Ask him to borrow it, then show up with Speedriven's 695 hp kit installed. Imagine the joy on his weathered face when he finally smokes ol' Chester's Black Series.

The kit, which costs nine grand total and boosts torque to 840 lb-ft, includes a set of Speedriven's top-mounted water-to-air intercoolers, "scorpion" air intakes, K&N cone filters, and ECU software to handle the added air density and boost—along with a transmission-controller upgrade the company says provides a more "true" manual mode and adds a more aggressive tune to Sport mode.

Grandpa will be the hit at Century Village's weekly test and tune.

[via Speedriven]