The 22 comes as standard with plastic rear hex's and metal front hex's.
The rear hex will not fit on the front as the rear's slide over the axle, locating on a pin and then screw tight, where as the front hex's create the axle by running into the bearings in the hub and being held in place with a screw. The exploded view on the TLR website
http://www.tlracing.com/ProdInfo/Fil..._explosion.pdf
helps to show how everything locates together.
Yes you can buy different off-set hex's, any UK model shop with a horizon account should be able to get them for you. I run the 1.5mm ones on my 22 and find that they help to make the rear end more stable particularly on bumpy tracks along with giving some extra forwards drive to as you said. The hex's have the offset engraved onto them so you should be able to tell what ones you already have on the car.
With regards to shiny bits, they always look good, but just remember where you may be changing the weak part in the car to as you could end up with an expensive or time consuming fix depending on what you chose to upgrade.