What suspension with 16x9s borbet a all round

[JS2010]

Hi I have 1989 325i with 16x9 borbet type a all round with 3mm spacers. 215/40/16

I would like to lower the car as it has stock suspension. The lower the better.

I have a fairly low budget and seen some coilovers on eBay for even less than £200.

What should I buy?

Will I have to roll the arches?

Thanks.