KatchC63

Hi everyone,

I've owned my 13 coupe (non P31 unfortunately) for 6 months now, Its not my daily so I do a lot of Santa Monica mountains canyon driving and I hope to track the car more then I got to.
I'm slowly modding the car. so far I did:
* CF splitter, spoiler Etc.
* ROW air-boxes & AFE filters
* Wave track LSD
* EC V6 tune
* Forgestar 19 rims
* Michelin sport Cup 2 tires (245F , 265R)

I'm debating what to do next and what would make the most difference in handling performance as I try to keep this mod fever somewhat reasonable or else I should have just bought a Black series.
I'm Considering:
* KW V3 vs H&R springs
* RB BBK rotors vs RB stock size rotors with better pads and new lines.

What would make the most difference & most bang for the buck?
Any other recommendations to improve handling performance?

thesaintusa

I have KW V3 on my STi and they are definitely worth it.

When I do the suspension on the C63 I will go with KW V3.

ML63 AMG

Definitely the RB Lightweight 2piece rotors for sure. If you are not tracking just get the stock sized rotors with the SS brake lines and Castrol SRF (Or motul660). The BBK has heavier rotors so the gains from mass reduction as less pronounced and actually not as good.

Remember that taking almost 40 pounds of unsrpung rotating mass will total transform how the car rides. It also makes the suspension able to react much quicker to changes in the road surface thereby improving suspension performance significantly as well. It will make your stock suspension feel like an aftermarket setup.

On top of that braking, acceleration and cornering are also improved just by changing the rosters. Not to mention it is also preventative maintenance.

Changing the suspension changes just that, whereas changing the rotors will change every aspect of the cars performance. Go with the Lightest RB setup you can, you will not be disappointed

KatchC63

Since I don't track the car very often but would like to, my dilemma is if I should shell out for the BBK or not and would it make a big difference in the track versus the stock size RB rotors?

BLKROKT

The BBK makes a huge difference on track vs stock rotor size, but only if you're going to really push the car. Keep in mind that with the BBK you can only run 19" wheels. And if you don't track the car, it's a total waste. IMO stick to the RB rotors in stock size with a more track-focused pad and braided lines.

KatchC63

BLKROKT I do track the car but plan to track more but I don't think I'm at the level of comfort where I really push the boundaries of the car on the track. Any thoughts about coilovers vs sport springs?

chrisridebike8

I'd stay stock suspension and use the money for track days or driving school. That will make you much faster and safer and ultimately be able to enjoy your car more. The stock suspension is plenty capable for the average driver.

KatchC63

I definitely agree about the track days and driving school but I also think the suspension as is set for more comfort and it's very noticeable when I push the car.
Anyone here has experience with sport springs that can shed light on how they compare to the coilovers?

AMG3.2

Have had them both back to back. As others have said, the stock suspension is plenty capable. I'd say it's just a hair softer than my coilover set up now at 9k front, 11k rear spring rates. I really liked the way the car felt with H&R Springs and surprisingly, the stock suspension handles the lowered ride height really well. H&R springs will also be harder than your stock springs.

The only reason I moved to a coilover is because I needed to go lower in the rear due to my HMS fender flares and couldn't do so without further adjustment. I do also like how I can fine tune the dampers to my liking though via rebound and set camber as well.

KatchC63

In your experience are the coilovers handle that much better that it's worth the over $2k difference?

Any issues with the stock suspension and the springs with the added stress?

I saw a post on the forum talking about steering pulling right with H&R springs, was that an issue?

AMG3.2

So I bought Muller MSC-1, as opposed to most on this forum that go with KW V3.

Coilovers definitely do have their merits so I won't knock the setup in general, but for someone that is fine with H&R ride height, and doesn't need the ability to set camber, or corner balance their car, H&R springs are the way to go. Another great thing about some coilover kits is the ability to change spring stiffness to your liking -- obviously something that cannot be done with H&R's.

Regarding the pulling to the right, yes, I did experience that but it's an easy fix at any alignment shop. For some off reason, when lowering our cars, the caster/camber settings go haywire. What you need to do is buy 1 or 2 of the OE fluted bolts and match the camber/casters as close as possible. Prior to me doing this, my car was pulling slightly on the freeway. After installing and bringing the caster numbers much closer together, the pulling went away.

There's a ton of my info out there on one of the "H&R pulling" threads as well as a bunch of other info out there.

Diabolis

Katch63 - if you're going to track a C63 with the MCT, you can easily end up overheating the oil (and going into limp mode)... depending on where you live, you might look into getting the 44O cooling package.

I'll second chrisridebike's sugestion about some DE courses (that will give you the biggest bang-for-the-buck in terms of lap times and also not destroying the tires & brakes on the car), and blkrokt's suggestion about replacing the brakes with the OEM size RB rotors and some better pads.