When I bought my plus 4 back in 2010 I wanted to fit a roll bar that would allow me to do my yearly amateur hillclimbing but that could also stay during all year. I was advised against a low roll bar for two reasons: a) it wouldn't help much in case of roll over; b) it would be dangerous to use without a helmet, instead of saving your head it could very well be what kills you if your head hits it unprotected.
So I went for a tall roll bar split in two sections, the lower half is permanent, the upper half is fitted when needed. It isn't the prettiest thing, but does the job it was made for.
