So u2sean recommendations are spot on.
seriously for a first pin this isnt a great decision if you are not mechanically or electrically minded.
That said.. 1100 isnt a crazy price if it has a clean and non damaged playfield, plastic, or back glass.
All the problems you read.. are around mostly the ground issues. Which are very quickly and easily remedied. Second to that are some electrical modifications to transistor areas (not on the main PCB/MPU) these are also easy and quick fixes if you are handy with a soldering iron and component soldering.
So if your confident as a tinker-er no worries if the PF and Back Glass look awesome for a 31 year old pinball.
If you are not, this is not the best pony to ride for your first rodeo. If you damage particular areas they are likely not replaceable, or come at a significant cost to replace. Turning your $1100 game into a $2000 game, and that price will be hard to recoup.
I just picked one up in awesome shape for $1500 it was basically "new" its likely my 3rd favorite game in my collection right now. this game is epic.
as far as LED's they are 99% plug and play. the only bulbs you can not simply "plug" are the ~8 bulbs that illuminate the "lower playfield" (again this is about a 5 min fix with a solder iron) you could however just leave the "orginal 24v lights" in place and replace all other bulbs with LED if you chose to.
@Fishbeadtwo thanks! it was fun getting your game up and running, I should mention its because of your game - I pulled the trigger on buying my own.
-Kelly