i started this topic a while ago and now ive learnt not to do seam welding yourself, my mates mazda rallycar was done at home and everything was welded continuosly (no gaps), well when i managed to stack his car there was no play in the joints and instead of the front simply crumpling, there was bends in the inside panel and even at the base of the a-pillar and this wasnt excatly a huge impact, i sort of slid into a ditch and hit a log that was lying accross the bank on the other side of the ditch, the front corner was punched in and now we are cutting out a new front corner to weld onto his car, but anyway i reckon with all the joins being so rigid the force has been transmitted further into the car and rather than loosening up and bending joints, these are now too strong instead the material bends in funny places. ive since been told that you should never seam weld in front of strut towers, so this area acts as crumple zone, and the idea raised before about increasing number of welds and length of them rather than welding up everything sounds like a good suggestion too.