Stuck between a wall and a hard place!

Hi everyone, We just went into escrow on our new place and planning some renovations before move in. One main project we are planning is opening this wall in the living room. Our new home is a solid wall, but many other same model homes in the community came with an optional pass through. Now I haven't opened the wall yet, but the box along the ceiling leads me to believe its a load bearing wall. With that being said, I'm hoping that the builders have already built this wall with a header and studs to distribute the load. My question is, if a properly built pass-through is already distributing the load to the outside studs. Can I remove the sill of the pass-through to make it an open wall instead of a 'window' pass-through? [i]Current wall[/i] [i]builder pass-through in other same model homes[/i] [i]sill removal of pass-through[/i] Ultimately, does the bottom sill portion of a pass-through provide any structural integrity to a load bearing wall?

I have been working on the foyer of my 200+year old home. I am almost done and ready to start dry walling. The 2nd floor floor joists (the ceiling joists in the foyer) are significantly bowed. I just replaced the 1st floor floor joists (sistered new ones in) but don't plan on doing the 2nd floor ones. but I am concerned attaching drywall to these would not look good. The old ceiling was a drop ceiling so this wasn't an issue. The span is 15' 2" and the joists are rough cut true 2x8. I started to put up some shims on one end since it wasn't too bad. the one picture shows a 1/2" shim on end, then 3/8", then 1/4", which continues for a long distance to about mid span. But the other end was really bad at 1 1/2" and really too much to do this. So I figured I would need to sister in a new nailer. other pictures show it in place and how far out the joist is on the end. Putting these are a lot easier than shimming. Is that the way to go? I was originally concerned about all the extra weight since the joists are bowed which is why I started shimming. but it is too much out to do it that way. I could scribe the 2x4, then cut it and screw it up on bottom of joist to avoid the extra weight. will need longer drywall screws to go through this 1 1/2" "shim" to do this. I don't think the joists are moving anymore? think nailers whole length OK? That is easist.