If your going for looks & on a budget then springs will be fine but as you've experienced the front might be a bit high. If you after sharpening the handling then I wouldn't bother buying springs unless you're fitting a rear ARB at the same time because it'll be next to no different than it already is without one.
Coilovers really sharpen up the handling, even without upgrading/adding ARBs they are pretty good but for a decent set of damping & height adjustable ones, you're looking at least £600 (K-Sport & D2 make good ones at this price) or perhaps £800 for KW V2, maybe even more for Bilstein.
Lowering the LCR on stiffened shocks and springs or
coilovers won't make you scrape as much as you think as there is less bounce in the shocks, this is why you normally scrape now.
As for the exhaust note, I haven't heard that one before. However, the sound of the exhaust does rebound off of the floor making it sound louder inside the car. Obviously, the closer you and the sound are to the floor, the less distance the sound has to travel back so you can hear it, also less sound is lost over shorter distances i.e. if a firework exploded in your face, it'd be alot louder than 1000ft up in the air
.
Sounds a little strange I know but it's all down to a bit of science really. I experienced this when I dropped my old Honda Civic to the floor.