Can anyone tell me if it's really necessary to have an isolator with electronic ignition?

I'm building a 3rd scale Extra 91" span but wont be ready for a while and want to by a cheap smaller plane using a petrol engine.

A Blackhorse Cap 232 80" span with a 45cc MVVS engine. It has electronic ignition, does this mean I need a isolator with that one as well? I'm trying to keep the plane light, so if I don't need it then I wont bother but if I get interference from the high tension lead then I'll need an isolator..... Is this true???


Kevin