First of all Im talking about a 95 SSE that Im fixing.
If I cut a hole in the roof (most of the roof out) will I loos a lot of structural integrity?
What do you guys think? will I get a lot of new rattles?

Depends on how much, but if you take a coupe and a convertible of the same model, a convertible has a lot more flex in the body, corners worse, etc.

Yep, and that is with a beefed up unibody as well. Granted, a convertible is missing its pillars too which provide a great deal of strength. Not really sure what to tell you Alex. How big of a hole, sunroof size, or roadster size?

Im cutting most of the roof out.
this is not my car, but just to show where im cutting.

I would definately reinforce things, because it would only take one pot shot to the B-pillar to ruin your day :?

What is going to be put in place of the current roof. Or will it be open? If its open, I would reinforce the opening. If you are going for a glass top, it will provide some strength.

I did add some metal all around, mostly to add strenght to the roof metal & to hold the water out when the top is in place. I will take pics and post them. havnt made the cut yet, because Im still not shure if to go fiberglass removable roof, or canvas clip on.
But what conserns me more is that the car holds together after I cut it.

I think it will be fine. Just make sure the bracing is tied together. The actual sheetmetal skin isn't holding anything together.

well that is the problem. I neet to cut the bracing under the roof skin. How do I tie it together after I have this big hole in the roof?

I would weld tubing to the bracing around the perimeter of the cutting area and then cut the bracing and roof skin all as one. Does this make any sense?