This is a great way to add "afterglow" cheaply, although plug life will be less than normal (duh). At next plug replacement time you could get the special afterglow-rated plugs which would help. A full factory conversion (for the 603) is expensive- you need the late relay, plugs, temp switch for the cylinder head, and some custom wiring... $200+ last time I checked. The relay+50C switch trick costs about ten bucks, tops, for a new relay. I've been meaning to do this on my car and haven't gotten around to it yet. Hmmm... maybe this weekend....
