Over on ClubGP, they tend to migrate to ZZP, since ZZP owns and sponsors that Forum.
On this Forum, you'll see people migrate to INTENSE for a couple of reasons. Their customer service and support is fantastic, and they pioneered a few things for the Bonneville, where the only Bonneville parts ZZP supports are those common to the GP.
INTENSE has pushed the limits of Bonneville Performance farther than anyone.
ZZP, Intense, and Thrasher are all good, proven vendors, but we probably have more experience with INTENSE here.
Both Scott Cook (Owner) and Todd Allen (Customer service manager) are members here, and own Bonnevilles.