The GPz1100 is a bit of a simple bike by today's standards, no real frills here. It is very comfortable for long rides and the engine is a real gem with lots of torque.
It's very hard to find parts as not many of them were sold, so nobody really carries them. The engine is very similar to the ZRX1100 though, so that does help.
The bike can be a bit ponderous at low speeds and it also prone to head bearing wear, which makes matters worse.