Budget M4: Track Build Breakdown & What’s Next

Now that you know the weapon of choice, let’s break down the one I actually found. This M4 took a few months to track down, which explains the gap after the Instagram poll. I was hunting for the cleanest M4 I could find under my rigid $30k cap.

In this article, I’m doing a deep dive into what I actually bought. We’ll go through the hard numbers, the tangible details, and whether this thing is a total piece of shit or closer to the ultimate track car, one capable of whooping on Terry and the boys.

This is a long one, so bookmark it if you can’t get through it in a single bathroom break.

Weight

The elephant in the room, quite literally, is that these things are not light. This one weighs in at 3590lbs, so it’s a lot of weight to move around. A 3,500-lb race car can be fast, but it comes with trade-offs. The extra mass works against you in braking zones, overloads the tires sooner in corners, and generates more heat everywhere (brakes, tires, drivetrain). Transitions are slower, setup windows are narrower, and maintaining consistency becomes harder over long sessions. It’s not unmanageable, but heavier cars demand better brakes, more cooling, wider tires, and cleaner driving to run at the same level as lighter cars.

Carbon roof + Lowering CG

The one option I really wanted, because it was super cool and labor intensive to do was the OEM carbon roof. BMW tried to reduce the car’s weight wherever possible. The roof, being the highest structure of the car, is not only lighter than a steel roof but also lowers the center of gravity. 

A lower center of gravity improves performance by reducing load transfer across all axis (acceleration, braking, and cornering), allowing the tires and suspension to work more efficiently. With less lateral load transfer, the tires remain more evenly loaded, which increases total available grip. A lower CG also reduces body roll by shortening the leverage between the chassis and the roll center, improving camber control, compliance over curbing, and overall tire contact under load. I enjoy hitting curbs, so it’s essential.

Beyond just grip, a low CG sharpens transient response. The car responds more quickly to steering inputs, transitions more smoothly (and faster) through direction changes, and remains more stable under heavy braking and during corner exit acceleration. A lower CG does not create grip on its own; it allows the car to use its existing grip more effectively.

FBO

It’s no secret that these modern BMW engines respond really well to full bolt-ons (FBO). Typically, with a tune and a non-restrictive downpipe, you’re right in that 500 whp neighborhood, and this F82 is no different. Conservatively, it’s tuned to 470 whp on 93. It also has E85 maps for a flex-fuel system, so I can put up to 85% ethanol in it and it’ll be fine. I don’t have any dyno numbers for E85, but I can assure you my butt dyno says it’s over 500. By the end of this article, it’ll probably be 600 for sure.

The car also has a valved exhaust, which is honestly perfect. Loud and free at the track, but quiet enough not to be that guy driving around the subdivision. It’s running intakes too, which makes the child in me ridiculously happy every time I hear the turbos doing turbo things.

Fortunately and unfortunately, the intake and exhaust don’t add much in terms of actual wheel horsepower. I’d say maybe 20 hp combined, and that’s really just a testament to how good the OEM components already are on these cars. However, with the power it’s making now and where the weight should land, I’m looking at a 6.0–7.0:1 power-to-weight ratio (lbs to whp), which should put this thing in a very competitive window on track.

Small Things

One surprise bonus was the P3 gauge. The F82’s multi-bus CAN system exposes a ton of usable powertrain and chassis data, which makes it perfect for external monitoring without the hassle of extra sensors. This setup lets me view engine RPM, vehicle speed, throttle position, boost pressure, intake air temp, coolant temp, oil temp, AFR, battery voltage, gear position, trans temp, pedal position, and that’s just a partial list.

That’s a lot of tappable info. Considering BMW doesn’t show you basic stuff like coolant temp on the factory cluster, this is a huge win.

Another solid touch is the Alcantara steering wheel. Microfiber grips better than leather, especially with gloves. In theory, it improves precision and reduces hand fatigue since you don’t have to grip as tightly. That all sounds like marketing fluff, and maybe it is, but it still looks great, feels right, and every track car kind of deserves one. Gloved or barehanded, it’s hard to argue with the feel.

Grip

To make my first time at the track a little easier, the car already came on 18×10 wheels wrapped in ADVAN Apex V601s, which are honestly a pretty decent starting point. They’re just a tad small for what this car really wants, so consider this a preview. I’ll be able to show you exactly how much tire this thing actually needs once we start pushing it.

The previous owner also fitted KW V3 coilovers, which have been great on the street and during spirited driving so far. I’m curious to see how they hold up on track, because they’re a perfect middle ground between high-end off-the-shelf coilovers and true motorsports dampers. Since I will be switching to a motorsports grade damper later, that comparison alone should be worth paying attention to as this car evolves.

First Date

So far, driving this M4 has been phenomenal. I know the internet is split on the steering, but for me, it’s a hit. Is it as good as an Alfa Romeo Giulia? Absolutely not, but it’s still damn good.
The F82 uses electric power steering with a variable-ratio rack that prioritizes stability over raw feedback. Like most EPS systems, assist ramps down at speed and under load to prevent overcorrection. It doesn’t have the texture of an old hydraulic rack, but it’s predictable and inspires confidence, at least on the street.

Traction control allegedly kicked in at speeds I can’t legally publish. That just speaks to how much torque the S55 makes, even at high revs. The acceleration is disgusting for a car this heavy. Coming from a turbo S2000, it still manages to surprise me.

My biggest hurdle on track is managing that torque from mid-corner to corner exit. This thing lights the tires off before your brain fully catches up.

What Now?

There are a few more things left to do. Before any more changes happen, I need a real baseline, so I know what’s inside and what needs addressing. I’ll walk through how I evaluate that. I also plan to dig into the competition and what they’re likely to bring to Grand Canyon Raceway, because that’s ultimately who this car has to beat. That breakdown is coming in the next article. So drop a comment below, let me know what you think of it.