Any particular reason to buy Quadro? It will suck ass in games, just so you know.
Btw, 3D is all about cheating. If you want to keep it simple, like doing still renders and maybe simple animations, then "buying out from trouble" can be the best solution. But if you want to do 3D as a more serious hobby or especially something you may want to work with some day, then you need to learn to optimize.
I recently out competed some Maya/mental ray users who applied for a professional project, because one of my main pro's is that I can tweak the heck out of a scene and make the hardware spit out whats required of it, even though I have 0% experience with Maya! 3D, cheating/optimizing and tweaking all go hand in hand.
Your lighting needs some work - the artificial lights are too strong and you need to add some filler lights, to emulate skylight (and even the artifical ones) bouncing all over the place.
Ppl who aren't too familiar with traditional 3d apps might want to have a look at Hypershot. It allows to do setups much quicker and easier than traditional 3d packages. Render quality is good and the app isn't a "noob" thing. Hypershot is aimed towards quick and easy renders, whereas 3d apps gives you the flexibility to do almost whatever you want - that in turn also means that the leaning curve is steeper, even for simple things.
Edit: hm.. it seems it can't be downloaded atm. due to some licensing issues related to the rendering technology - they are working on solving this.. keep an eye out.
The biggest issue there can be with motionblur, is rendertimes - even if it's just a single frame, it's not always you may want to wait however long it will take to complete the render.. so the tip:
Lower the reflection quality of the rims/tires - typically ppl have blurred reflections on them, and you can easily get away by dropping the quality. The more motion blur you want, the more you can drop the quality.
Yeh, the illusion of car floating is easy to get when using lightsources that casts too soft shadows (HDRI, big area lights and whatnot) - btw.. is that why your shadows so dark.. to "hide" the float effect? :P Cuz i just think they are too dark.. again :P
You should look into Ambient Occlusion - You can use it for the entire render, or as a "contact patch" only. If latter, then apply it only on the ground and tweak the settings so the AO has the desired effect.
You could also use regular lights, and these can give better results. But this method required a lot more work and tuning.
Could be, but not if you only used the tools described in the tutorial - but in this particular case its not. I'll explain further below.
Indeed - looks much better now
My lack of experience with 3DS/VRay prevents me to guess why you had black windows. I would have said ray depth optimization at first, but that can't be it. If it was, then the small render should have had black windows. Not the bigger render.
Sure, but I think this thread would become boring fast if all ppl did was to show renders, and never wrote anything.
Some notes: I glimpsed over the tutorial quickly - The render you have goes to about step 19. The author doesn't explain what he does after this step until he later opens Photoshop. The final render has a brighter car, and because of the difference in camera angle, I can also see clearly that the background is too dark. You can see the sun setting, but the glow is grayish - it shouldn't be (it's grayish because the quality of the HDRI isn't good - but thats normal with many HDR images).
I can't say exactly what he did - what I would do, would be to adjust the HDRI settings (I think it's called Multiplier), so it becomes brighter and more natural looking, and then render that out.
It explains why you are getting bad reflections (again, bad HDRI quality). Your reflection transition goes from red (car paint), blue tint (slight reflection of the sky) gray gray gray gray. There should be more detail. The sky in your HDR is simple, but there is gradient - you should be able to get that in your reflections.
Basically - the way the HDRI is affecting the reflections is no different than using a non HDRI as background.
In pic #1 you can basically see straight through the glasses, but in pic #2, you can't, even though glass refracts more than water, which is what's in those glasses. The empty glasses "aren't refracting more" because of volume/thickness. Glasses are thin, so the effect is little. That's the issue with your rendering. The windows are flat, but in 3D apps that doesn't mean they are thin - it actually means the opposite. You need to add some thickness if you want to do true glass material.
BUT.. I'm also saying that refraction on car windows is so little noticeable, that you can avoid using it altogether, and more than often no one will ever notice - and your renders will be quicker.
There is still a way to go. The numberplate you are seeing looks very much like a wrong texture close to where the gearshifter is. Look closely, and you can see the shifter itself It also apears like there are 3 front seats and this is because you are using heavy refraction. Don't use refraction at all. Even realistically speaking, the refraction on car windows is so little that it's barely noticeable - but even then, you'd need to do some modeling to archive that. Just stay away from refraction.
It also looks like you are using some sort of a tonemapping filter - look at the the bright reflections on the front window and the hood - they are gray and "squashed" - very unnatural looking. You need to tweak the tonemapper so that bright reflections don't get clipped that much (before you ask: a gray sky doesn't equal gray reflections - that's why HDRI's are considered realistic vs. regular images as for instance backgrounds).
A note on tonemapping: You should avoid using it. It's advanced stuff for ppl who understands lighting. I may be wrong, but I will assume that you don't know the full meaning of it - if that's true, then you could end up tweaking reflections (because they look gray) when you shouldn't: because it's the tonemapper causing the reflections to look off - or the light or colors to look off.