[Veselin Kolev]

I would recomend NOT using Bosch 30x30 or 20x20. My old team used this a few years, and the chassis was always heavy and expensive. Bosch is metric, so you have to use metric bolts and you have to buy the special T-nuts, which are rather expensive. Also, the connectors are expensive, and rather weak, especially for 20x20. I can estimate that our Bosch chassis from 2003 was around 600 dollars with all the bolts and beams and connectors, and weighed a solid 30 lbs, and was still kind of weak.

If you are looking into extrusion, try to go for something customary. Bosch sells an inch series, and there is also 8020 and lots of other extrusions that are in inches. Inch series is less annoying to work with (no conversions, as FIRST is generally inch-based), and less expensive because there are more common parts, like bolts and T-nuts.