Altering the front chain ring or guard is not required if you get an IHG.


You don't need to alter the front guard unless you get a 56 tooth chain ring. Altering a D9 54 tooth to a 56 does not make a lot of difference.You dont need to with dual drive , but changing from 54 to 56it adds a little more top end for 30 MPH +, ( a dual drive fitted to an otherwise standard D9 set up of 54 /11 works fine also)
If you use 56 tooth with the standard mezzo 54 chainguard it does not cover the teeth, and you need a birdie or bike friday or Mezzo D10 or 56 t Ori version.


The shimano nexus 8 speed is overdrive from gear 6 upwards,
The stermley archer hub 8 speed they are 1;1 first gear then over drive in each gear. so a SA IHG less of a problem to over come the need for increasing gearing on small wheeled bike. So you might want to gear a SA hub down by making the chainring smaller.

replacing a 54t for the 56 tooth and a birdie chain ring is just an expensive but minor change.

Its not a value for money upgrade but at least its simple and offers gearing the mezzo up by around one gear.