I haven't heard of those.. smurfields..longfields.. but not the profields. All sounds like they are treated to last. Doubt it would be hard to tell the difference between them.
Longs are 4340. If you go through the hassle of buying and replacing the birfs, might as well get the strongest out there. $99 is hard to beat though. Get 'em, try and break 'em, report back.
