Just a mouse, admittedly I bought a better than average gaming style mouse, I do PC gaming and my old Microsoft mouse was getting tired. They are just better made, higher quality feel and switches. Also the one I bought has a programmable button below the mouse wheel which switches the DPI resolution, really all this does is reduce the amount of on screen movement vs physical movement so you have better fine control when you need it.
I have had a play around with a tablet and they are great for freehand drawing, but the pen types can give you hand cramp after a short time and most the time I am working it can be 2, 4 or more hours. Also most of the work in Sketchup I am moving something in a defined axis, where you click and hold then by tapping an assigned key for a directional movement it locks the part to move in that axis, quick and easy and no benefit with a tablet.
1/6th that's the size of a car!
Glad to be an inspiration, I think with all these kind of things you have to get past the procrastination point, where you feel it's almost too much to take on and is it worth it. Getting started and feeling like you have accomplished something is a good motivator. Plus when you start and make progress it suddenly seems much less of a task, still easy to get demotivated by spending too long on one thing. I got exasperated with the front when I discovered what I was trying to copy was "wrong". It made me think is it worth it, what is right? Then you just have to realise it can only ever be something like 98% right, there will always be small errors.
I doubt if the creators thought it would be something obsessed over this much time later, wasn't it said that the guys working on Star Wars just hoped it would do ok at the box office?