Just wanted to share some info in case anyone finds this useful. I'm happy to be the guinea pig, albeit on a different car.
I've lowered a 2002 Toyota Rav4 on Koni yellow struts/shocks with H&R lowering springs and
lowered a 2005 Mercedes c230 Kompressor Sports Sedan on TEIN basic coilover kit.
With stiffer suspension, bumps will feel extra bumpy and on the flip side, smooth asphalt will feel like driving on the smoothest surface you can think of it. Basically, it will exaggerate the texture of the road.
My impressions:
Rav4:
Going springs alone are definitely cheaper, but yes as others have mentioned, the ride will be harsher. The reason why is that b/c the ride height is lowered, it needs to compensate bumps in the road with a much shorter range. It does so by being stiffer so the car doesn't bottom out. The Koni yellows (damper adjustable) and H&R lowering springs combo was great. No one believes me, but I swear it drives like my mom's Mini Cooper S. I can turn a lot tighter and at much higher speeds. As for being bumpy, I gotta explain. Having stiffer sportier suspension is like jumping on the ground vs jumping on a bed. The impact to the ground is harsh, but it's just once. The impact on a bed is tons less harsh but it bounces over and over and over until there's no more bounce. So when people say "bumpy" as uncomfortable, you have to decide whether you think bouncing over and over and over on a soft suspension is more annoying or a quick harsh single slam is more annoying. The advantage of stiffer suspension is that you can take corners a lot better w/o the whole car feeling like it's going to tip over to the outside edge.
C230:
The TEIN basic coilover kit is not damper adjustable. It's designed mostly for looks. It's only height adjustable, so if you don't like the softness/stiffness of the suspension, too bad. You bought it, you installed it, you live with it. For mine, it was definitely not as harsh as the stiffest setting on the Koni's (yes, I realize this was on a different car). Although it's supposedly a sports sedan, it doesn't take corners as well as my Rav4 once did. I know, hard to believe, but that goes to show you how much of a difference suspension can really make. To be completely honest, I think part of it has to do with the Rav4 being 4 wheel drive with better control vs the c230 which is rear wheel drive and tends to oversteer and the rear can potentially skid (and I have both on purpose and unintentionally).
WHAT ANY OF THIS HAS ANYTHING TO DO WITH YOU:
Firstly, if you are pregnant, plan to be or have frequent passengers/drivers who are/will be, don't mess with the suspension. In my Rav4 experience above, I can feel my organs shaking and getting headaches. It's dramatic. I got used to it, but it's not a comfortable feeling for most people, particularly passengers who aren't experiencing the advantages first hand of improved cornering.
- If you're on a budget and are going for the lowered look and don't mind a bit of a harsher ride, get springs only. Do NOT cut your stock springs. There isn't much tolerance and you're likely to bottom out.
- If you're willing to spend a bit more but aren't really that hardcore about it, add some sport shocks/struts with the springs. I'm a fan of Koni yellows.
- If you want full height and damper adjustability for various drivers or driving styles/types, go for the coilover kit. The softest suspension still won't be anywhere near the softness of stock. Don't think you're increasing your range of adjustability to include all suspension qualities.
- Bagging it? Air suspension. I've recently become very interested in this, but my budget won't allow it and I have zero experience with this setup. No clue other than I think it looks cool that you can lower so much and raise the car to clear driveways and curbs that you normally wouldn't be able to with standard suspension types above. This most likely will require a big tank taking up trunk space. Not worth it for most people who own CX-5's.
WILL I BE LOWERING MY OWN CX-5?
Highly unlikely. Wife is the primary driver. She doesn't like stiff suspension. The suspension on it is actually quite stiff relative to what I'd expect out of a crossover. The only other one I've driven is the 2015 VW Tiguan and Toyota Rav4. If I mess with any suspension, it'll be on the next car where I'm the primary driver. With my driving being a lot less "spirited" after being a dad, I'm more on the slow and cautious side these days anyway.