I am a suspension novice and looking for aesthetic improvement only. Don't mind harder suspension however.

Looking to achieve a small drop (20 - 25mm) with coils. Change is for aesthetics only, but in doing this don't want to impact on overall suspension performance (in normal/semi-spirited road driving only). Can I purchase said coils over the counter (Pedders?) Is what I am proposing a huge no-no and will risk destroying the suspension performance?

Any advice is appreciated.