Our E91 GTS Tribute Adds More Power, Cooling, and Efficiency to its Growing List of Accolades

Photography: PSI Media Team

  • The Pit+Paddock x Bilstein E91 M3 GTS is building momentum toward its SEMA debut as Precision Sport Industries (PSI) tackles must-have engine upgrades from CSF, Eventuri, Future Classic, Carbahn, and Alpine Motorsports.
  • CSF’s racing division offers a one-stop upgrade for the E9X that includes a triple-pass radiator, oil cooler, and DCT cooler.
  • Eventuri’s carbon fiber intake and plenum introduce a CSL-inspired tonal quality into the cabin and raise the theatric barometer of the Carbahn 4.6-liter engine.
  • Future Classic’s plug-and-play billet oil filter housing cap and extended power steering reservoir set help dissipate heat and maintain steering feel when all the fluids get hot.
  • Alpine Motorsports is a remote tuning outfit that helps BMW owners improve the factory recipe — including the sharper GTS shifting parameters on the DCT gearbox.

Building a car requires dexterity as much as it does skill. Precision Sport Industries (PSI) has been an automotive polyglot throughout — flexing its seemingly limitless capacity for considering every feasible detail in equal measure to its proficiency to, for lack of a better term, get things done. The progress on the Pit+Paddock x Bilstein E91 GTS Tribute has been swift, requiring PSI’s team and our own to become fast friends to ensure we stay on top of each critical step and record terabytes of the journey along the way. By no small measure has this been an easy process, but fortunately, determination has been the unstoppable force that has propelled this project forward. With SEMA only a couple of weeks away, there hasn’t been any time to spare.

Today is a big day, perhaps one of the most pivotal thus far. The Carbahn 4.6-liter stoker engine has settled into its new home in the E91’s Fire Orange bay and, once all of the supplementary engine mods are installed, it means we can finally wake up our wagon for the first time. Before getting too far ahead of ourselves, let’s unpack what we’re diving into.


There’s no bigger name for BMW cooling upgrades than CSF. It’s been able to extract more than 50 years of dedicated engineering to build robust solutions that stand up to rigorous street and track abuse. CSF’s E9X M3 cooling package addresses all of the car’s factory shortcomings. It adds a triple-pass radiator (7059), oil cooler (8025), power steering cooler (8041), and DCT cooler (8042), which should help keep our Pit+Paddock x Bilstein E91 GTS Tribute, well, cool. The net effect of all this work is a car that reliably stays beneath critical temperature thresholds while also rebounding from peak figures faster thanks to a 30-40% efficiency improvement. As an added bonus, the entire package is “drop-in fit” — even the oil cooler — which is a standout CSF benefit.

The suite has been trusted in some of the most demanding motorsport conditions — including the 25 Hours of Thunderhill — where CSF’s endurance and temperature resilience are tested in equal appraisal.


Modern manufacturing has afforded companies the opportunity to imagine all-new solutions to even long-standing problems. Eventuri is a prime example of this; the UK-based company combined its years of Aeronautic and tuning experience with 3D printing and CFD analysis to create proven performance. Because of its new approach, the UK-based company has set a new standard for induction — a segment never previously held by legitimate horsepower claims — and carbon fiber engine accessories.

The Pit+Paddock x Bilstein E91 GTS Tribute received a generous allotment: Eventuri’s carbon fiber plenum, intake, intake lid, and duct set help infuse the cabin with intoxicating CSL-style intake noise, all while providing significantly higher volumes of air to the motor. The combination is a big improvement in sound and throttle response and, as you’d expect from a product of this caliber, was a straightforward plug-and-play install.


Future Classic is an exercise in product and visual design. Within that framework, creating high-quality products and lifestyle goods for late-model and modern BMWs and Porsches have been singular focuses. The E9X crowd has been one of its biggest markets since the company started five years ago, and as such, Future Classic contributed two important billet aluminum upgrades to the engine bay: a new power steering reservoir set and an oil filter housing cap. 

The reservoir set — which includes a billet aluminum cap (the factory cap is plastic) — adds over 35mm of fluid expansion to maintain precise steering feel at the limit. This additional headroom acts as an overflow area, allowing the fluid to rise into it rather than spill out and all over your engine bay. Though the exterior features are familiar to other alternatives, the Future Classic reservoir is machined from a single piece of 6061-T6 aircraft-grade aluminum which eliminates the need for internal gaskets and with it, the need for servicing over time. The billet oil filter cap is a much more robust piece and is more proficient in dealing with heat dissipation than the factory (again, plastic) unit.


Alpine Motorsports is an automotive tuning company that offers remote tuning and coding. Aside from some must-have coding features for the chassis, we had Alex flash our DCT transmission with updated GTS shifting parameters. This should help sharpen its response time and accentuate the Pit+Paddock x Bilstein E91 GTS Tribute’s intended character.

Since the laptop was already out, it was as good a time as any to load Carbahn’s required 4.6-liter engine software. The remap ensures the Pit+Paddock x Bilstein E91 GTS Tribute will have balanced performance that carefully considers deployable power and torque across the rev range. The right recipe here helps manage smooth delivery, which in turn makes the car easier to trust when it matters most.


With all the engine mods sorted, it was time to wake this beast up for the first time. After brimming the motor up with 10 liters of fresh MOTUL 300V 10-60 oil, we brought the Pit+Paddock E91 GTS Tribute to life. As I alluded to before, seeing and hearing this wagon run in the shop marked a big step forward for the project. It was a notable reward for the PSI staff that has worked so hard to get the project to this point. You got a sense that although it provided a small sense of relief, this milestone seemed to motivate the team even more. In the end, that’s a good sign because there’s still plenty to do before its grand unveiling on the SEMA show floor.

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