Whats this then?

[5tox]

http://www.ebay.co.uk/itm/Mk1-2-Esco...item256f2e50c9

What exactly does this lot do then, does it weld onto the chassis rail and eliminate the need for an anti roll bar?

what are the benefits?

[Roadsport]

it steadys your front wheels during braking. Keeps it where it is as where the ARB flexes and allows the tyre to move thus altering the tire angles. And you get adjustable castor.
Some say it does eliminate the need for ARB but I'd say in a serious go fast application you'll miss one soon. Thats where the drop links come in.
And yes you weld it to the chassis rail.

[exboyracer]

It's a compression strut kit, the idea is that this locates the wheel longitudinally instead of the arb.

You would still need an arb to control body roll (either that or very stiff shocks and springs)

The main advantage is it locates the wheels much more rigidly than the standard anti roll bar which can bend under heavy braking.

[5tox]

so realyy id still need the arb with this working alongside it

[evodave]

so realyy id still need the arb with this working alongside it

If using compression struts, you usually go up in spring rate if not using an anti-rioll bar.

Cheers,
David

[Roadsport]

Thats pretty much your options add ARB or use significantly stiffer sprins to avoid excess body roll.