i dunno where your shocks are set but on changing the pre load for the springs. if you dont have a tool,it can be done with channelocks. you dont have to but it doesnt hurt to get the rear wheel up off the ground some and loosen the bottom to compress it and take the load off the shock you are doing. then put it back and move to the other side.
the taller springs of new shocks cannot hurt but the cartridge on the cheap shocks are going to wear out faster than progressive or similar ones. hell even new stock shocks were worn out in a couple of years and it was the springs doing the work. a long time ago around 1980? there was a really heavy dude come in the shop wanting stronger shocks on a early wing. after discussion and looking at expensive brand name m.c. shock prices he agreed and we welded the new mounts to put a set of cheap automotive monroes on it. it was stiff,they lasted a couple years and he just replaced them when needed.
i wouldnt want to hammer on a new exhaust either but on the stock one it would not really matter. it is a old exhaust,its on the bottom out of sight and it's not like it needs much. a few weeks ago i had to slightly hammer the inside pipes of a friends n.o.s. three hundred dollar four in one collector so the oil filter cover would come out. even new most aftermarket stuff almost fits but i have never seen much that did not need some mods to make it work no matter what section it goes on.