There is no free lunch. Lowering springs increase the effective spring rate to prevent bottoming, that means more stress on the shocks and you are effectively under-damped now. The harder you push the car, the more problems you'll generally have. You will have a stiffer and more bouncy ride. Lots of people say "they are fine" or "it's not bad", but again, nothing is free. If you want to retain a controlled ride, especially at the limits, you need higher damping rates. I was kind of lucky with BMW where my shocks were electronic and I could simply get a "shock flash" that increased the damping rates to match the stiffer springs. The stiffer damping rate also helped a lot with the stiffer sways, to dampen the side-to-side action when one side of the car would hit a bump. While still not ideal like actually changing shocks, it was a lot better than just doing springs by themselves.
Sometimes the lowering spring isn't actually much, if any, stiffer, relying on a stiffer bump-stop, but this means the suspension is moving faster into the deep travel on something like a pot-hole, having not been slowed by the combination of the spring and damper, putting more stress on everything.
Also, sometimes lowering springs are a one-size-fits-all. The company claims to make "lowering springs" for multiple models/trims of the same car, but you go and check the part numbers and they are all the same part no. That is bad because cars weigh different amounts. There were a lot of companies offering lowering-springs for my BMW, but only one of the two that actually analyzed each car configuration/trim and adjusted the spring rates for each weight made one for my car and I had to import them from Europe. Differences of a few hundred pounds in car weight are significant. This is usually due to different engines and drive configurations.
This doesn't mean you'll just die instantly if you do a drop, but there will be compromises. The compromises will vary with the drop. You will put more stress on stuff. One of the most common issues with lowering springs is busting the shock/strut hat where the shock connects with the frame of the car. I've seen this on many different makes. Again, doing a drop doesn't guarantee this, it's just what could go wrong.
Yeah, you'd need an alignment if you are changing the geometry, like lowering springs do.
I've had many lower cars and the old subaru with it's giant nose and the engine in front of the front axle helped me learn. You never go "in" any place that you are not sure if you can get out of. You go park somewhere else or keep driving until you find something nearby. You don't get yourself "stuck". You can handle a LOT of stuff by taking it at an angle, anything from a slight angle to a crazy angle and one of your wheels may hang in the air for a little bit as you transition (but you won't scrape the car).
My rule here is that I wouldn't go lower than the lowest OEM configuration, there's just no good reason IMO and I'm not into "show cars". I like a low car, low driving position, etc., but function trumps everything else. Suspension is needed for bumps. There's often a good deal of leeway between lower-specs and the higher-end specs though, like the most aggressive version of the car will be 20mm-40mm or more lower than the lower-specs. If you want to do it right, you get adjustable shocks (struts) to dial them into the springs. There are sometimes aftermarket non-adjustable struts that are dialed for lower setups.
The best way to do it is always coil-overs, able to set your height and adjust the damping.
