Crashing is also caused by a lot of sketches in assembly or part. Never constrain parts to sketches in parts unless really needed. It was a known problem in our company when beginners were having difficulties with constant crashing of solidworks.
Are you sure you want to give 3 mates to bolts. Solidworks has to calculate that 3rd mate. When it is undefined it doesn't it rotates wherever and frees up memory. Give it a try. Mate 20 Bolts with 3 mates a piece (60 mates ) and 2 mates a piece ( 40 mates) and evaluate the performance.
When inserting an assembly into a larger assembly as you did with suspension; do both assemblies need to be sharing a common origin? or is a mating process
