Add-on packs for off-road racer MotorStorm and Ninja Gaiden Sigma along with two demos mark this week's update to the PlayStation 3's online PlayStation Store.

Priced at $5.99, MotorStorm's Revenge Weekend pack adds the new Coyote Revenge track, five new vehicles, nine new events, and the Eliminator online mode to the repertoire of Evolution Studios' gritty racer. Alternately, four of the new cars can be purchased separately at $0.99 a pop.

On the demon-killing ninja front, owners of Team Ninja's Ninja Gaiden Sigma can snag the $2.99 Weapons Master download, which adds more spirit-crushing challenge in the form of a new survival mode.

As for demos, PlayStation 3 owners can now sample Midway Chicago and Tiger Hill Entertainment's Stranglehold, as well as EA Canada's NBA Live 08. Both demos are also available on Xbox 360 via the console's Xbox Live Marketplace.