We’re planning to upgrade a Visual C++ 6.0 project with 1500 classes to Visual Studio 8.0

a) Is it worth to upgrade our project from one compiler to the other? Which would be the main advantages to support this decision?

b) Shall we see a clear decrease of speed while editing code and resources, compiling and linking our project with such big number of classes in the Visual Studio comparing to the results in Visual C++ 6.0? Shall we meet any other typical problems due to the upgrade of a big project from one compiler to the other?

c) Should we upgrade our Visual C++ project directly opening it from the Visual Studio 8.0 or should we start a new project in the Visual Studio and then progressively incorporate the old classes into the new project?

d) Should we change our native C++ classes to managed C++ classes while upgrading to Visual Studio, or should we maintain our classes as they’re defined?

Thanks a lot for your help!