It appears that your frame is the exception and this will not be a problem. I've been riding a BBS02-equipped steel hardtail off road for six years (twice a week, 10 - 15 miles) on pretty hilly, eroded trails in socal; it's neither needed maintenance nor failed. Don't worry about your chain; mine has never been a problem, but just in case carry a multi-tool with a chain breaker and an extra link. Check Suspension Fork Perks if your fork has elastomers and don't worry about the performance unless you're really riding demon-like. Many have used these off road for years.