How low do you want to go? I only wanted a slight lowering to clean up the look after I got my new wheels so I went with H&R OE Sport Springs (.75/.5" drop). It's exactly what I wanted for my needs (daily driver with frequent passengers and a steep driveway entrance).
I had springs on all cars before this one.. I'm on coils for the first time and love them. Very smooth ride and I can fully customize. Mine (installed) cost quite a bit more than $600 though..but then again with springs, in most cases you should be getting shocks as well and that drives the price up to $600 easily.. $200/springs and $100/shock.
I mean what is your budget? I would look into the HT-spec Type 1s. At a price of $600, I think they are pretty aggressively priced. I'm really not a springs on stock shocks type of person. This way you can get the exact height that you want and get dampening that will be better with the spring rate.
Depends how low you want to go, coilovers are adjustable so you can go way lower then springs. Also keep in mind that if you get just springs, your stock shocks might blow in the future because they are not designed to be lowered.
I'm on Tein H-Tech luxury springs with stock shocks. The ride is decent but the ride can feel under-damped on rough roads or over dips in the road. I'm thinking I'll probably upgrade to neuspeed sport springs with koni yellow shocks (Supercup kit). The Supercup Kit does give you the option to raise or lower the ride height using the adjustable perches on the koni yellow shocks.
I'm not a big fan of coilovers because I think they aren't good when you decide to sell the car. People don't want coilovers on a car when they buy it IMO. If I look under a car and see koni yellows I know I can replace a shock but if I look under and see coilovers especially non-rebuildable ones I wouldn't be interested in the car. I guess if you plan to remove them before selling the car it's not an issue though.
here is my take on it. If youre just looking to drop the car, go with springs, mind you though by going this route you're going to be limited to wheel/fitment/stance. springs are a cheaper route, however i hope that youre factoring/taking into consideration that you will need to run aftermarket struts like KYB, depending on which model you go with struts youre looking at 150-200 a strut. Now, you might think that coilovers are not viable alternative because you dont "race" your car, but it gives you the adjustability you may want/need in the future. just as an example, brand x springs will drop you 2.5 inches, after settling it can drop another .25 or so, our stock wheels are 17''s, depending on tire size you might start to rub. but brand x coils can drop you say 0-4 inches, give you adjustable camber caster plates up front and adjustable dampening, thus making it easier for you to fit larger diameter wheels so on. for the price of coilovers youre getting your moneys worth imo. the hubby had fitment issues when he ran springs on his car, 17x8 on 205/40's rub, which is why he switched up to full coils, now he's running 18x10 +18 on 225/40(herra frush) and 17x10 +25 for track wheels, and having the ability to raise and lower the ride height at will is definitely worth the extra buck imho.