The Corvette was designed as a convertabile. There hard top offers little in the way of extra rigity. I don't think it would be that big of a deal to lose a little panel on top of the car. I think it is the same reason it doesn't get leather. Keep it simple and affordable.
thanks for the info guys.but 1 more question:there are 2 buttons and one knob like swithches left of the stearing wheel right below the left vent by the door.what are they for?i need to know all functions of those switches.and also how do u post a picture?
Albert, my boy. Cutting a hole in the top would decrease the diaphragm strength of the cabin's top panel. Since there's little in the way of a cage, that added resistance to twisting of the chassis is significant. Yes, extra weight up top -- especially for a car that's noticeably taller than other sports cars -- is bad, but very minor issue compared to rigidity.
celm, I can not find pics, but I believe one of the buttons is for the IC water sprayer. I also think some countries have adjustable leveling headlights, that could be what the other is for. The knob could be like the one on my Legacy, for the dimming of the dash lights. Don't quote me on this though.
The painted outer "thin" sheetmetal and the velour roof liner are the only items cut. All structuaral members A,B,C-pillars and outer longitudinal rails are left intact. The "slim" sunroof is around 14-16" and is squeezed in-between the A&B-pillars so as not to compromise chassis strength.