Always intended to make a pair of ramps to suit the 155, will get round to it one day...........when I make the de-cat pipe too!!!
Agree with the comments above, spanners, sockets, rubber mallet, decent pliers, snipe nose(check the jaws and make sure they are parallel)allen keys etc ......I would avoid mole grips and adjustable spanners, tempting as they are you will destroy most things unless you're used to using them (sorry if this sounds patronising!)
I usually buy mid-range tools. You don't need the real expensive gear and avoid the cheapo market stuff like the plague. It will destroy the job or will self destruct as soon as they get near the car!
Other more specific tools come with time as you attempt bigger/more complex jobs............just remembered, a decent oil filter wrench is useful too!! Oh, another must these days is a set of TORX bits (look like a star instead of hexagonal allen key).