Tried the super 4's on my XR.

Waste of time and money.

I have the Super 4's in my LPG AU motor and I have no problems, I don't think I would put them in again as I don't see any gain in using them. I got them because I like the idea of redundant spark paths with LPG and wasted spark, it needs to fire first time and every time.

i reckon super 4's are a bit of a gimic as the spark will always go the shortest path, so unless the electrodes are all gapped the same it will always use the same one.

gas is much more critical to have a good spark all the time. i'm pretty sure you need a colder plug compared to petrol. wrong heat range plugs in a gas car will foul up a lot quicker, cause pinging and also contribute to backfiring.