To add my tuppence-worth, I had 30mm Eibach lowering springs fitted on my NC earlier this year. At the time the garage who was going to do them suggested I didn’t and said I would find the ride too harsh and ground out on speed bumps etc. Since I’d already bought the springs I went ahead anyway. The difference in the handling of the car was noticeable the moment I drove away. Much more responsive and less roll meaning you can go into corners that bit quicker and not feel like you’re going to be flung out the door! I don’t find the ride any harsher and have not yet ground out on speed bumps (and we have some big 'uns round where I live). A week after having the springs done I spent a weekend driving around the Peak District in pretty atrocious weather but still had a smile on my face.
With regards to the bump stop issue mentioned by a few others, I believe there is a modified bump stop you can fit that is specifically for use with lowered springs. Pretty sure it was someone here on the forum that told me although I’ve not yet felt the need to investigate that further.
As for wheel alignment/geometry set up, I was originally going to go to WIM and have a fast road set up but was advised by a friend in the trade to keep to the standard set up unless I was intending to use the car for track days. As I understand it (and no doubt someone will tell me I’m wrong), the fast road set up is basically good for track days when you want good handling at speed on straights but the compromise is it is less effective in corners. Since most of us don’t do track days and a lot of us like to go blasting around twisty country roads, the benefits of fast road set up are less obvious. To be fair, I’ve not driven a car with the fast road set up so can’t speak with any authority but IMHO the standard set up will do you just fine for everyday driving so I’d suggest you save your money for some other mods instead…
When I was talking about getting my suspension sorted and that my main use would be having a blast round peak district B roads the first thing that was mentioned (by someone in the know) was a fast road setup.