There are many different types and kinds also sizes of extrusion that your able to get. One reason we used extrusion last year was the ease of it compared to making all the frame with the 1" aluminum like we did in 2003. It cut back on time, money and human resources because all we had to do is call the nearest dealer and they would send us a piece for our frame instead of cutting and welding the pieces together. The nuts and bolts that the extrusion come with are very strong and hold up through many competitions if used correctly. here's a
website that i have as a favorite from last year, even though we never ended up using them we had a dealer about a half hour away that was very generous to us. I hope all of this helps you and can't wait to see what your team builds this season.
Pit Bull
P.S. If visiting the website go towards the bottom for the FIRST special...