The exhaust valve that Hondas have (at least in the '03 954) is a single click that is audible once as you pass 3k rpm's. Yeah, it sounds like that click/ping noise, but it's not repetitive. It's simply the sound a metal flap would make opening up inside of a metal exhaust pipe. IMO, I don't think that's a possibility. I'm not much a fan of Hondas, though, so I've never really kept up with quirks on their recent lineup.