My 300SE had its timing chain snapped while I was at 140 km/p! Fortunately it was still under the workshop warranty period, and they fixed it up for me.
All the pistons and valves were gone, and had to be replaced. Somehow, I'm just baffled how the earth could the timing chan snap when it was just replaced a couple of months ago. Anyway, from what I saw, it certainly may be a sport for a gifted DIYer, but it was certainly a lot of work involved.
Got it all fixed in 2 days at no charge.
126 tailed by a 203, 129 leading the pack.