I went from an S10 to a Colorado (Z71), and am quite happy and
satisfied.  There is plenty of headroom (I am 6'3").  Engine does roar
a tad during heavy acceleration, but it is a NICE roar.  It does NOT
sound like a 4-cylinder, and has plenty of power.  

Head room seems ok to me.  I am 5'11".

The power is hard to figure becasue it doesn't jump like a 4.3, but it has
the power.  I pull a 16' Waco jon boat with outboard, fuel, three batteries,
and lots of gear.  Maybe 1000 or 1200 lbs total.  It doesn't leap like the
6.0 in my Silverado, but it pulls it in high gear at 65 mph without shifting
a lot on small grades like my S-10 with 4.3L.

It does have a funny sounding idle.  I would not confuse it for an inline 4.
The only thing that bothers me is it sounds rough when you are crankying it
for that split second from when the first cylinder fires until it is running
on its own.  Maybe only for a half a second.  The ones I started on the
dealer lot sounded the same way.

What I think makes it seem to not have as much power is the computer.  It is
programmed for soft shifts.  If you don't watch the tach you harldy notice
when it shifts at all.  I think it is also tuned to not allow hard
acceleration.  It has plenty of get up and go for passing, but it doesn't
have that sudden slam of a V-8 or a lightly loaded V-6 when you stomp on the
peddle.  Basically it feels like the computer won't allow that to happen.
It doesn't feel like it won't do it.  I say this because it will surprise
you.  Pulling the boat I mentioned earlier,a nd with some extra gear in the
bed I was decided to pass a line of boats on the way home from a torunament.
I put the peddle down and pulled out to pass. It shifted down, and it just
kept winding up and I kept gaining speed.  I just stayed on the throttle
until I was past the line of trucks and boat.  That's when it hit the rev
limitier at about 100MPH.  Oops.  Not bad considering it had a heavy load.
It was so smooth and pulled so steady throught he entire run that I would
have guessed my speed at about 85 until I looked at the speedo when it
stumbled on the rev limit.  I think the computer just keeps it very tame and
well mannered.

You know, I didnt really pay attention to how the colorado accelerated,
although it wasnt g-force acceleration, I thought it was compareable with my
4.3 in my S-10. My Silverado sh.t's and gets, I havent driven a full size
4x4 pickup other than the Dodge 1/2 ton with a hemi. I like the feeling when
I stomp on a vehicle and it throws me into the seat. I am starting to like
the inline family more and more, and I'm considering either buying a
Colorado, Caynon, or a trailblazer or possibly even a Envoy. But I'll need
to test drive the Envoy/Trailblazer with the 5.3 Liter before i can make my
final decision. One more thing i hated about the colorado was the plastic
dash, it was foamy. Plastic scratches to easily