depends on the kit and the vehicle. if you keep swaybars attached and aren't going silly high I wouldn't think it would be a big deal in an 80 series. take of swaybars/make disconnects for offroadtime.
RB30 in any patrol would be puss as shit unless it had the crap supercharged out of it. pratols are really heavy.
biggest problem will be if you raise the 4wd up, your tow ball goes with it so the arse of your trailer will drag pretty damn close to the ground, Just keep it in mind
yea would probably run an adjustable/custom removable one. Trojan make some to suit this kind of problem