Are you sure you're not scraping the flaps under the front bumper?

 

I think that's what it is because my rub marks are stretching a cross the sidewall of the entire front driver tire. Passenger side isn't rubbing though.

 

I just realized what you meant "flaps" and no, it's most likely the wheel arch fender liner that's rubbing

 

By rubbing, is it constant when the car is rolling or only on dips and speed bumps? You're not talking about the inner fender liner??

 

big bumps/dips only. Happening only on front driver side, not passenger, rear not rubbing at all. Yeah, I’m talking about inner fender liner, probably closest to the fender side.

 

I think it's best to go 20mm spacers all around, that's what I'm running and have't had any rubbing whatsoever.

 

I haven't seen much talk on your concern about how aggressive they feel so i thought i'd chime in. Springs for cars like the 3IS generally won't see much of an upgrade in aggressive or sporty feel as they're 1) for a luxury sedan and 2) meant to work with the stock shocks. Spring and shock specs are tuned to work together.

Aftermarket companies know that consumers for cars like the 3IS want an "easy" mod so they don't typically create an overly aggressive spring that would *require* an upgraded shock. Yes, typically aftermarket shocks would be better on all lowering springs just because they can usually handle the shorter travel better, but these spring manufacturers don't typically offer that information to you or spell it out on their sites. They basically offer a product that aims to lower the car while staying close to stock spec (feel). This allows the stock shock to keep performing as opposed to having a spring that is way too stiff to allow the shock to do any real work. Snippet from RSR's site:



To get a more aggressive feel, you'd want to go with a full coilover system. They're usually meant for more 'serious' performance and tend to increase the spring rate and shock damping to a higher degree. For more sportier applications there are usually racing lowering springs, but for our cars the choices are more limited and usually more weak sauce.

 

I removed the flaps because anytime I went over a speed bump or drove through something super low they scraped and it was annoying haha. I'm really happy the down springs do not drop the car so low that the actual car bottom outs, etc.

 

When you removed the flaps, have you noticed your engine bay getting more dirtier? I've heard it messes with the aerodynamics of the car? I'm thinking about removing those too, but they flex when scraping so i'm not too sure.

 

I honestly haven't noticed any differences at all, I was a little worried too that I would lose like 1 MPG or so but nope same gas mileage and stuff.

 

I have noticed that on a bumpier segment (say a bumpy stretch on highway), my car feels more unstable and shifts around especially in the rear. My friend said it's because I need an alignment done. On OEM springs, the car felt cohesive but on the springs it feels like the front and the rear are separate, is this normal?

 

You know, I gotta say I noticed this too. I have been thinking it’s my tires since the rear tires are almost gone but it’s been a while since I’ve had new tires back there so I’ll have to see how the car does once I get new tires here soon.

 

Alignment would definitely be the first thing I'd check, then tires. Having that said, it could just be a "normal" side effect of lowering the car. When the car is lowered, the stock suspension arms sit at an abnormal angle and can cause any sort of odd behavior, especially when said abnormal angles are even more pronounced upon going over extra bumpy areas. Or your shocks could be worn and not absorbing bumps as well as they should be. It could even be that the shocks are slightly hitting their bump stops....hard to say. Could be any number of reasons.

I would inspect the shocks and see if there's any leakage. Test if the shocks are hitting bump stops. I would get a fresh alignment from a reputable shop, then if that doesn't change anything, test a couple of other sets of wheel/tire combos to see if it changes behavior. If not, then you may want to start looking at trying to set alignment back to as stock spec as possible, like getting camber arms, to see if dynamic camber over bumps is what might be the cause. Modifying cars can be fun and also annoying

 

Mmm it’s not really an issue for me really. I have camber arms and I had just gotten an alignment from my local Lexus with everything in spec. It was more just something I noticed. My IS only has 22k miles so I don’t think it’s anything being worn.

 

@swaangin Did you end up re torquing your wheel spacers after 50 miles? if not are your lugs still tight? Thanks.