Dude, this is sweet!I love the level of detail and thought behind it. I have to agree with zoomzoom though it is kind of dark. I reckon it would look stunning in desert or snow cammo to bring out all the lovely detailing and hard work.
I use plugins, if you're interested in getting into 3d design then i wouldn't recommend sketchup unless you just want something to get a grasp for 3d modelling. Sketchup is actually not too bad for starting out. It would be worth your time to get into 3ds max (or maya) since it's free for students (If you're not a student you may be able to find a workaround to get the student version somewhere). The problem with sketchup is that it's only really useful for architecture and to an extent static models like this which require quite a few years of experience. Sketchup does have advantages, mainly that it's super fast and relatively easy to learn (especially when compared to 3ds max) but after a few years it becomes obvious what the limitations are.
Anyways if you do choose to go with sketchup here's a list of the plugins that i use, you can find most of these on the Sketchucation.com forum
Twlight Renderer ($100 and not on sketchucation, cheapest renderer I found for what it has) Round corner by fredo Artisan for sketchup ($50 and not on sketchucation) Fredo6_fredoscale Fredo_JointPushPull Curviloft by Fredo vertex tools for sketchup ($20 i think and not on sketchucation) Fur Tools, (not exceedingly useful for me)
One of the most useful things I've found in terms of educational value for sketchup is this list of shortkeys, if you memorize these and at least basically understand them you should be able to go lightning fast. www.sketchup-ur-space.com/2013…
If you're really interested in getting into 3d modelling don't stay with sketchup for too long unless you only want to use it for architecture. I've been using mostly only sketchup for 8 years or so and i haven't even been able to animate something until recently. If you're messing around or wanting to get a good grasp for 3d then like i said before sketchup is a good place to start.
oh and don't buy sketchup pro, it's not really worth it.
Let me know if you have any specific questions about sketchup.