Lowering the car too much will alter the suspension geometry and can f*ck up your handling. Likewise, It will cause unpleasant rubbing once you step up to bigger wheels and tires. If you lower your car 1.8"-2", this is not likely to be a serious issue. Its probably a good idea to get a camber kit if you lower more than 1.5".

Also, changing the spring rate too much without changing damping (shocks) can make your car handle worse, so regardless of your short-term plans, at some point you should step up to better shocks.

That said, it sounds to me like an intermediate lowering spring (something like the Eibach pro-kit) would be pretty good for what youre looking for. It'd lower your car about 1.5", is managable without a camber kit, and is soft enough to maintain decent handling and ride with stock shocks.