Surge protection that won't affect dynamics

Would like to know if there are any products out there that give surge protection only for high current flow and won't affect dynamics. Thanks
PS Audio Ultimate Outlets, its a no brainer. I have tried these on huge amps, subs you name it, and they have all been improved by the sound of the units.

Vansevers "Unlimiter".
Chang Lightspeed 9900 Amp: 30 amp rated current capacity, does not constrain dynamics, contains integral transient protection (oversize metal oxide varistor) & fusing. Four hospital grade outlets, spike feet, optional upgrade (even larger) AC input cable is also avilable from factory.