i think my dampers are maybe worn now , i want to replace with something equivalent to original parts , would bilstien b4 be a suitable replacement ?

dont want lowering or hard ride , but dont want sub standard parts not as good as vw

or suggest alternative small budget

The B4 is not good parts. Bad feed back but I install them on my 106 and I have no problem. You can try this.
But I prefered B6. I try this on my golf GTI and the confort is good.

B4 is suitable if you want part similar to original one
B6 is a little bit more « sport »

You can also try Sachs