Hobbit Smaug is awesome...if you're worried about doing stuff to it - make sure all the "fixes" are done already. Some games (maybe all Smaugs, I'm not sure) shipped with a few things that JJP sent out kits to correct. For example, if the game has the thin metal bendy ramp flaps, it needs the strong black newer versions. If it doesn't have the beast ball trap kits, it needs those as well. There was also a revision to the right wireform return. The original has a "break" in the rail by the bumpers...this often causes the ball to fly off. Later games had a revised rail that hugs the ball all the way around the turn, and plays perfectly. If you have the old wireform, you'll probably have to buy the new one...unlikely JJP will send a freebie on that one.
I had my Smaug for 2 years with minimal issues...other than installing those fixes I mentioned, I had a ledge on a drop target bank break, so I had to replace that...other than that, smooth sailing.