Very nice car OP, wish you the best with it. Get your mechanicals sorted first like wishbones, bushes, ball joints, RTAB's LCAB's etc etc before spending any money on further lowering modifications IMO. If your still on standard OE shocks with the current lowering spring then there are the possibilities the shocks are going to be pretty worn and fitting new lowering springs to them will knacker them out even quicker.

Bear in mind that when doing lowering springs if they have not recently been changed or documented as being changed then you should ideally replace your top mounts also as you will be removing the front shocks to install new springs and the rear shocks are easily removed with the most time being taken getting to them. So consider factoring in the cost of new front and rear top mounts when doing the swap. Again something small but whilst you are at the front and rear shocks install some M3 front reinforcement plates and Z3 rear reinforcement plates to help spread the load on the shock towers, this is preventative maintenance and well worth doing whilst everything is out.

I too have an E36 318is and it started out life on standard msport suspension, I then installed a used Eibach Pro Damper and Pro spring kit which I rolled around on for about 3 months. It was comfortable but offered a marginal drop over the msport suspension. I then moved to a new set of JOM coilovers which IMO (for a budget coilover kit) were excellent and very comfortable. I drove on the JOM's for just over a year with no issues. They were then swapped out for a used but great condition set of HSD Mono Pro coilovers which I found too harsh. The end result was a set of BC Racing fully adjustable coilovers and I have not looked back since.

The BC's were a big outlay but they are very comfortable and offer 30 way damping adjustability, come with adjustable camber front top mounts and static rear top mounts, new drop links and the height can be altered very easily. I have recently bought an E36 318i Msport touring and would like to go the BC route again but I want to keep it as close to OE as possible so in this case I have opted for a set of H&R lowering springs and am very much looking forward to trying them out. If you can hold out about 10 days or so I should have them in and can give you some feed back on them when I update the thread. If you would like to have a chat with me about anything just drop me a PM with your number and I shall call you to see if I can be of help.

I demand to see a thread on the E36

Hope this helps,