I have one extension for my Sweet 16 ... it works great.
It definitely is handy to have and is well designed for strength.
Also versatile in that the same extension can go on the right or left ..... and you could purchase two, if you wanted it both sides.
Being that mine was bought here in Canada, the price would not be relevant to you.
Just call your local dealer and ask the price .... and ask the price!
For me, it seemed pricey, but is well worth it.