When we heard that the surviving members of Detroit proto-punks the MC5 -- guitarist Wayne Kramer, drummer Dennis Thompson, and bassist Mike Davis -- were reforming as DKT/MC5 for a tour, our first reaction was ''Right on.'' But that changed to ''Say what?'' after hearing that the trio would be augmented on many dates by ex-Lemon-head Evan Dando and singer-songwriter Marshall Crenshaw. What kinds of jams can those cats kick out? ''Well, Marshall is from Detroit,'' says Kramer. ''And even though he mostly plays acoustic, he leapt at the chance to play electric on MC5 songs. He's a rocker.'' And former sweetheart of the alt-rock rodeo Dando? ''He called up out of the blue and demanded the gig,'' laughs Kramer. ''He started singing songs on the phone to me. He said, `I know 'em all. Here, I'll sing one. Listen to this!' I said, anyone with that much enthusiasm, let me get out of the way.''