I'm an easy fit into most cars... I'm just over 5'10" and 150 lbs.
Unfortunately I have a very high "ape factor" (my arms outstretched fingertip to fingertip are 5.5" longer than my overall height) so I often have a real hard time finding the right seat position where my arms are comfy using the steering wheel and the shifter. Usually if I set the seat for my arms to be happy I end up having to scoot closer so I can depress the clutch fully, then I feel all bunched up around the steering wheel. I could always do the "ghetto slouch" and recline the seat way back to make the arms feel better, but I refuse to do that. LOL.
The ape factor thing is good for rock climbing though, and the low weight means most of my friends usually let me race their karts/quads/bikes since they pick up a ton of speed with me on them.