hi.
Tubular suspension systems is one outfit that do various kits, and have drop in bags for the rear, that simply replace the spring.
have a look on their website, you should find everything you need to know there.
rubbing will depend a bit on your wheels. i had one of their full kits on my calais, and the rear guard lip touched the tyres at full drop when i had ROH 18x8's with 245 rubber. but didn't touch on the stock rims.
i had the guards rolled for clearance, and peace of mind.
the system was pretty easy to install. Specially if your just doing the rear. am not sure what your local state laws are with regard to self levelling and stuff, best check that out. (pretty much anything goes here in NZ.. provided you get a cert)
pro's
having a lowered car, but still being able to clear driveways and other obstacles.
pumping them up for heavy loads.
looks mean as when fully slammed. haha
very smooth ride at open road speeds.
cons.
finding places to fit/hide the tank and gear.
compressor noise (when it refills the tank)
my low speed, round town ride was really harsh when i ran it quite low.
