Should I use Ds when taking curvy roads or just leave it in D?

What about the manual? I've read that I won't be able to hurt it because the onboard computer will not let me, but I have no idea how to drive manual but I like to use it because it's fun, I just don't know how to properly use it. Is it OK to let it redline in first before changing to second? Is there any benefit to that? Is there any issue with riding in 3rd gear at 60-70 mph besides fuel efficiency loss?

Does anyone have any idea how to properly use manual mode when driving on hills? I've read some people (and I think the owners manual mentions this) that say it's better to be in manual when going up and down steep hills, I understand going down as you can engine brake which would help your brake pads from fading but I don't see the point when going uphill, any advantage over D?

I just drove the car on 1200 mile road trip and I'm about to make that trip again in a few weeks, can't express how much better it is than my last car (2002 taurus). Love this car

 

It is faster, provides batter gas mileage, and performs better leaving it alone and in D.
If going down a continuous steep grade, that is probably the only time you should use Ds, to keep your brakes from over heating.

 

And all that in 1200 miles. That VQ/CVT must be a tough one, probably not for long though.

 

I left it in D for basically the entire drive, but I'm not really sure what you mean?

 

Manual mode is faster on a curvy road because of the use of engine braking to help weight transfer etc... and "D" is faster in a straight line.

 

Nope, Ds will never be faster. You loose time between 'shifts' and the trans is programmed to keep you in the power band sweet spot.