Plastic washers on the back wishbone hub
 

Hello,

This is probably a silly question, but can you add 4 washer on the rear hub at the front or would this just cause issue?

You mean on the hinge pin/hub?
Washers on the front instead of the rear?

Yes thats what I mean, I wondered if it would give the car a little more length

Is one of the (many) adjustable features of the car. Knock yourself out.
A few of the team set ups have it this way round and I've been running it like that as long as I can remember.

Oh cool, I will more than likely knock a marshall out :p

so are there any other mods like this one without buying anything?

LOL, dozens.
Have a rummage thro the team durango build guides for your car (it is a 210 isn't it?) they will cover the majority of the standard adjustments, and explain the effects of each.
The instruction manual should cover a fair bit of it as well.
Then you've got the team drivers set ups to look at as well.....

Yep, im currently running mine in full length at the rear (4mm of spacer in front of the hub) and full forward at the front (spacers all behind the C-Hub). Makes the car more forgiving in loose conditions.

Im also running a +1 toe in bar at the rear as well, though this is a tuning option you would need to buy, that would also help settle the rear of the car if thats what your trying to achieve.

Perhaps put up where you race, the surface and size and then your current setup. Most drivers on here will be able to guide you with what you have to get the best from it.

I am running on a high grip track on astro at Silverstone club, I just wanna make the car a bit more forgiving as I have only been racing for about 6 months