Just got one of these myself
Long time lurker, first post;
I just picked up a 2012 SX4 to serve as a little commuter car, road trip vehicle, and fire road/light offroad fun vehicle. We're in the Pacific Northwest so we can see a bit of everything - snow, mud, rocks, and desert.
It replaced a stock Montero Sport with mud tires, so I lost quite a bit off offroad capability. We pushed that truck about as far as it could go and got a good decade out of it.
I had been planning to lift the SX4 with the RRO kit, but was a bit dismayed to suddenly find a bunch of reports about strut threads breaking with the lift kit. We almost always drive solo, so the prospect of having that happen up on a mountain somewhere was not going to fly. I spent a couple of months trying to figure out how to squeeze out a little more ground clearance than just adding larger tires. Eventually I managed to get some part numbers for springs for the European models that I could order via Amazon without costing an arm and a leg for shipping. The non-US models apparently have a higher ride height.
I was a total noob to any suspension work other than easy shock absorber swaps. I got a lot of practice, since I put the strut top bearings back together wrong and had to take them back out and reassemble them. (I'll get some part numbers and links for the springs up when I get home. Took me a few weeks to find something that Amazon would ship and which would fit, digging through cross-references).
The springs seemed to be both stiffer and just a bit (~ 1/2") longer. End result: I gained about an inch and a half in the rear and an inch in the front just in suspension lift, plus the ability to carry a bit more without sagging. The amount of lift is with the thicker front and rear skid plates from Primitive Racing installed, although they honestly don't weight all that much. I then gained a little more with 215/65 R16 Grabber AT2's.
I think the huge front skidplate reduces wind noise quite a bit, and the new AT tires are actually much quieter than the worn out OEM tires I had on before. Ride quality is fairly similar; the tires soak up a lot of bumps, but the stiffer springs still seem to make it corner a bit nicer on the road. The only disconcerting thing is the lateral sidewall flex when hitting potholes on a tight corner, although that's probably made worse by the marginally effective stock rear shocks.
Gas mileage is almost unchanged; not accounting at all for the odometer being off, my average commuting MPG according to the dash display went from 24.7 to 24.4
I hope to get some pics up soon - I still have more mods to do. I'm working on getting a full size spare in the wheel well, getting my tools secured, an additional 12v outlet, and replacing the factory rear rising cargo cover with a fixed cargo shelf. The front interior could also use some more storage nooks for longer trips. Eventually I'm also planning on setting up a roof rack for a gas can and some Maxtrax sand mats.
I'll also put up some measurements from a level surface so anyone with a stock vehicle can compare.
Edit:
Weather isn't cooperating right now, so I don't have measurements. Springs:
ADK888337 REAR COIL SPRING
ADK888335 FRONT COIL SPRING
http://www.amazon.co.uk/dp/B00B8ZAYTI/ref=pe_385721_37038051_TE_dp_1
http://www.amazon.co.uk/dp/B00B8WYAVY/ref=pe_385721_37038051_TE_dp_2
I also forgot to mention another important mod - rodent-proofing. The factory plastic guards to keep critters out of the passenger air intake are not at all sufficient for keeping out small mice. When I replaced the OEM cabin air filter you could see that some mice had tried to nibble on it. After removing the plastic at the base of the windshield I made an aluminum mesh box out of some gutter shield and screwed it into place over the intake. I need to do the engine airbox as well, soon.
