1995 325i convertible suspension help?

Hi:

I am in the process of replacing the struts and shocks. My car at the moment has 15 inch wheels, but I am planning on mounting 18 inch wheels. I have 3 questions. First, how can I figure out if my car has a sport suspension system? Second, I see that shock companies have sport and heavy duty type of shocks and struts. What type of struts and shocks do I need? What type of brands are good? I was looking into bilstiens, monroes and koni str. And finally, would I need to change the springs if I want to mount 18 inch wheels? Thanks everybody for your time and knowledge. It is surely appreciated.1995 325i convertible suspension help?
Well i have been looking int this myself too. i want 16s on my e30 but anyway putting larger wheels on the car means there will be like a ';thinner'; tire so there wont be as visible from the side if that makes sense, just the wheel will take up more space, but the diameter of the wheel and the tire together will be the same as it was originally. BUT if the wheel has a wider base then you might need to roll you fenders i think ??? : / . to make more room fr when you turn them. So, sport shocks and springs will lower you car about maybe 2'' in the front and 1.5'' in the back, this will create better handling and less body roll but possibly a less smooth ride because when coupled with springs there's less space so there needs to be more tension, so its not as absorbent. Heavy duty springs shouldn't lower the car i think, maybe a little, but are just built to provide best ride and shock absorbency. so it depends on what your looking for. im looking to get bilstiens because they seem really well reviewed and are german too so they go together lol. konis i hear are good ant i think have adjustable ride height or something like that but lots of people are pleased with them, never heard of monroes because im focused on the bilstiens. ohh and to find out if it has a spot suspension, if it hasnt been swaped then its stock, and even thought its might be a ';sport'; suspension its really not, im guessing maybe its a second owner car? but check the labor records and or call the previous owner or something, OR also take a look at them certain shocks have different colors i dont think you can tell in the front since theyre hidden inside the strut mount. Anyways hope this helps