so I’ve bought a shiny new (non carbon) stem to hold on to my also non carbon bars, but it has a torque rating on. I don’t own any torque wrench keys, so can I get away with just ‘standard’ allen keys?

You can of course, but a Torquekey ain’t gonna break the bank.

http://www.superstarcomponents.com/en/5nm-torque-tool.htm

Nice one, thanks for the link.

Check the torque setting is 5Nm, otherwise a torque key isn’t ideal… They’re excellent if it is though.

at least be assured of one thing. its a useful torque setting marked on a stem. i always chuckle when i see bars with a torque rating.