It's very much down to preference and that is the distinct advantage over set ride heights and set damping. IMO, there's no match dude.
I was in your position about 6 months ago and the price tag was really appealing in terms of Eibach springs, but when I read and re-read reviews on not to match springs with stock shocks, it put me off... suspension is a major part of your car And I wouldn't feel comfortable knowing I might have saved a few hundred quid but ran the risk of a poor quality of ride. Why do that when you've paid presumably a considerable amount of your hard earned cash on your pride and joy.
BCs are excellent quality coilovers (otherwise I certainly wouldn't have them and neither would someone with an E92 M3 lol).. I did a lot of research and there were FK, Apax, etc etc, entry / budget level ones for £2-300 but steer clear! You're better leaving your car as is if you start considering them lolll..
I'm praising BCs because that's what I and few others have (very popular amongst Scoobys) and I feel a significant difference in ride quality. You also get that mean lowered look and the beauty is you can keep tweaking it and tinkering till you get the perfect drop for yourself... and then under the bonnet.. tweak your damper settings which btw are 30way.. so you can certainly achieve a desired ride Q plus height..
Do lots of research and reading
as mentioned HotCoupe has some brilliant coil overs and for that money (see classified), I'd not hesitate. Superb highly regarded coil overs.