5nm is max torque. You don't need that much unless you have slippage issues, use carbon paste and try 3nm.

Also people use grease on the bolts, this increases the effective tension in the bolt, if you use blue loctite you have less chance of over tensioning.

Finally, pinch the bolts a little at a time, do the bottom a turn, do the top a turn, repeat to spec.

I personally prefer Ti bolts as I find my sweat (and riding in all weather conditions year round) corrodes steel ones.