kesmarc

Hello, soon i will switch from a c43(2017) to a c63s(2015) because i wanted the v8...
What are the must do mods you need to do for power?<

For exemple i had on my c43 stage 2 tune + downpipe puting me around 480hp...
Is it the same thing for c63s or there is more things do to ! thanks

CT-AMG

The single most important thing to do is to change the tires and go UP in size. The factory tires suck in anything but summer temps and dry weather. Change them and go up to 265/285 from 245/265.

My opinion, this was the best thing I ever did..

Strafe1

Maybe so, but a sacrifice in steering feel and overall handling. Unless, of course, you get wider wheels.

CT-AMG

Thats a first for me. I've read dozens of posts from people who increased tire size and I have never heard a single such complaint.
I feel no such loss in handling or steering feel. In fact, I feel the car handles significantly better and has more rubber on the road.
The rear tires no longer spin freely with the slightest touch of the gas pedal and it is more difficult to get the rear to break loose.

Couldnt disagree more with your comments.

AKnight55

Lowered

Wexlax732

I disagree as well. I was astonished at how woefully inadequate the stock tire size performed under power. Going to a 285/35/19 rear and 255/35/19 front was the best choice to date with my car. (Michelin Pilot Sport 4S)

Delete the secondary “cat” for sound and then tune with one of the many available options.

dlefty

MUST:
-downpipes
-tune
-adjustable springs
-better/bigger/wider rubber and if in budget wider wheels

Strafe1

I felt a bit more straight line traction in the rear with wider tires, but less precision on turn in with wider fronts. It defies physics to have an over extended sidewall perform equal to or better than a properly fitted/stretched tire. As far as posts by other owners, I would question the same. If your basing your conclusion on traction off the line, then ok. But there is no way the car is more precise with tires that don't fit the rims they're mounted to. I'm talking about tires out of spec with the rim width, not just a single width size larger, which are likely still in spec. If you've ever autocross with "fatter" tires, you know what I'm referring to. Completely different story if mounted on wider wheels. You can feel the difference even at 6/10ths. I'm not sure what parameters you are using to gauge handling. As long as you like it, that really is all that matters though.

Wexlax732

Coming from a 15’ STI, I learned a ton about performance and handling when I started to auto X the car. One thing I learned is that deviating from manufacturer spec on the actual wheel comes with a large list of caveats. I most likely won’t ever change the wheels on this car, but the tires I went with (285/35 & 255/35) compliment the car perfectly and don’t bulge over the wheel at all. I went with 285’s on my 9” wheel w/ the STI and holy crap was that a mistake. The car turned into an under steering pig on the track. I use my car mainly for roll racing, highway rips and the occasional run through some twisties. If I auto X’d this car, I would start messing with suspension, wheel width etc.

TBH, modding this car is fun but a serious concern monetarily. Not only are the parts taxed to hell and back due to the emblem our cars bear, but god forbid you add downpipes and a tune then pop the motor.... say hello to a $71,000 bill for a new motor. Worst case scenario, you now have a really pretty work bench in your garage that takes ~5 years to pay off.