lowering by 40mm on std shocks is ok, as long as you use decent springs. eibach etc... not gmax or anything halfrauds can offer.
40mm just takes the ride height down a little bit, looks alot better than standard, but doesnt really do too much to handling in my opinion.. but there again, i've only driven cars that have had the springs replaced with pants gmax.
my golf has shocks and spring set and it makes such a difference!
rob