On the other hand, Using the kitbot frame could save you two weeks of design/build time. You can do alot to a manipulator/shooter in two weeks. The weight difference to our teams extruded frame was negligable, and the strength of the kitbot is anything that you would need for FIRST competition. We have used the kitbot frame for two years now and have been strong competitors for both of those. There is something to be said about having a driveable base a week after kickoff.
The one thing I would suggest improving though, is the et of wheels that comes with the kit. While they'll get you where you're going, they are by no means the grippiest wheels out there. There are numerous things you can do to increase their traction, but there are also quite a few alternatives.
Colson Wheels are one of them, but there are a number out there.
If you are worrying about CADing a frame, then look to
Extruded Aluminum.
Welded frames are fine and dandy if you have an experienced welder at your disposal, but if you don't exactly know how, they can result in a lot of wasted material and a mediocre end result.