depends how low you go on cheap ones, from experience if running sump scraping low the ride comfort suffers quite badly, if your only going 40-60mm then it's not so bad, i've know cheap ones and expensive ones to be quite similar at slammed levels and both tend to pop seals too, when fitting i would suggest on the fronts make sure you jack the hub up before you tighten the bolts on the shocker so your wheels have negative camber rather than positive, only fractional if using the standard bolts and doesn't have adverse affects on tyre wear provided the car is tracked after lowering
when doing the backs get some new mounts, if the old ones have been on a few years they will likely squeak if refitted
if you dont have a drop head 22mm spanner for the fronts then the easiest way to loosen and tighten them is with a spark plug socket, an allen key and an adjustable spanner, put the socket on, put the allen key through into the strut and the adjustable on top of the socket and turn the socket anti clockwise and the key clockwise, opposite for fitting, the lower bolts are usually 17/18mm
with the rears you will need a 17mm spanner and the adjustable again, the first nut on the top of the rears just holds the little plate looking thing on, then when that's off theres another 17mm that's holding the shocker on, best way to do it is remove from the top first as the drivers side lower bolt is behind the tank and passenger side behind the exhaust, if you've undone both tops then the beam will drop down (provided it's not where you put the jack/axle stands) thus clearing obstructions, the lower beam bolts are 17mm and the nuts in the ends of the rear beam are 15's