I am trying to identify a good base layer type shirt that also has some body protection built into it, with an emphasis on back/spine protection. Ideally something minimal, but still effective, and very form fitting. The IXS flow shirt seems like a good candidate. Prefer sleeveless, or at least w/o pads on the arms. Anyone with real world experience? I really dont wear a pack anymore but I ride pretty rowdy trails at high speeds (Pisgah) and I'm feeling a bit too exposed. Obviously is will be warmer than what I'm used to but anything that breathes well too is a preferred.