A stainless steel header like borla will no way crack as easy as the stock cast manifold. I haven't heard of anyone having issues with a SS header. I have the a steel pacesetter header with the armor coat on it, I have had it for 2 years with out issue. Nothing is unbreakable, but I don't see where you could go wrong with getting a good name brand SS header. Some people could break a cotton ball, I wouldn't worry about it. I don't know a lot about banks, but borla makes some top notch equipment.
1987 wrangler, 258 I-6, 5-speed.
2007 liberty sport 4X4, automatic
2009 ford ranger 4x4 FX4 OFF/ROAD, 5-speed