Jon, I'd recommend use of a torque wrench for head nuts if nothing else. The main benefit is even tightening. If you are heavy-handed it might save you from a sheared stud now and then.
Don't buy second hand. Choose one with a range which is appropriate for the job you want to do - a '0 - 250' won't be very accurate at 20. Not really worth buying a cheap one - if it's not accurate and consistent it's a waste of money.
I'd suggest visiting a proper tool shop and asking for their recommendation in your price range. Mine was made by Norbar and is still pretty accurate after quite a few years.
Proper engineering workshops have torque wrench calibration gauges and regularly use them - even good wrenches lose accuracy over time.
You won't find many published torque settings for an A7, but they are good for heads nuts, big ends and centre mains. 0 - 50 Nm would be a useful range.
Don't buy second hand. Choose one with a range which is appropriate for the job you want to do - a '0 - 250' won't be very accurate at 20. Not really worth buying a cheap one - if it's not accurate and consistent it's a waste of money.
I'd suggest visiting a proper tool shop and asking for their recommendation in your price range. Mine was made by Norbar and is still pretty accurate after quite a few years.
Proper engineering workshops have torque wrench calibration gauges and regularly use them - even good wrenches lose accuracy over time.
You won't find many published torque settings for an A7, but they are good for heads nuts, big ends and centre mains. 0 - 50 Nm would be a useful range.