The 2018+ F90 M5 is an absolutely insane car from top to bottom. It's no secret the S63tu4 engine in the M5 is severely underrated from the factory. BMW quotes the F90 M5 competition model at 617 horsepower and 553 torque. In reality, this engine puts down about 620 horsepower and 600+ torque to the wheels. It doesn't stop there, either.
BMW leaves a lot on the table, and the S63 is capable of massive power gains with a tune and bolt-on mods. Among the best bolt-on mods lies a set of upgraded downpipes (DP's). In this guide, we'll discuss the benefits and power gains of F90 M5 downpipes and list the best products on the market.
*This article is specific to the 2018-2021 F90 M5. If you're looking for downpipes for the F10 M5 or F12 M6 (2011-2018) then check out this guide.
BMW M5 Catless vs Catted DP's
We'll somewhat dive into the specific performance gains of catless vs catted F90 M5 downpipes below. However, this post is primarily focused on catless options as they offer the best bang for the buck. The idea of a downpipe upgrade is to reduce back-pressure. F90 M5 engines use 4 catalytic converters in the exhaust - 2 primary and 2 secondary cats. They help reduce emissions, but come at the cost of worse performance.
That's where downpipe mods come into play. Again, the goal is to reduce back-pressure so completely eliminating the cats provides the biggest power and performance gains. High-flow cats are less restrictive than the OEM downpipes, but still aren't as effective as removing the cats. High-flow F90 M5 downpipes are also generally a lot more expensive.
F90 M5 Downpipes Upgrade Pros
A few benefits to upgrading the F90 S63 DP's include:
- 30-50whp (15-30whp w/ high-flow cats)
- 40-60wtq (20-40wtq w/ high-flow cats)
- Faster turbo spool
- Awesome sounds
- Easier on turbos & engine
The power gains with F90 downpipes are probably the most tempting reason to upgrade. There's a lot of power on the table due to the massive restriction from the 4 cats. Catless M5 downpipes are going to offer nearly twice as much power and torque when compared to high-flow DP's. The benefits of downpipe mods don't end there, either.
Reducing back-pressure is going to result in drastic improvements to turbo spool. The F90 M5 turbos are able to breathe more efficiently, which will also result in some awesome exhaust notes. Finally, the reduction in back-pressure is healthy for the S63 engine. It helps get rid of hot exhaust gases faster thereby reducing exhaust gas reversion and lowering exhaust gas temps.
BMW F90 Downpipe Sounds
We think the F90 M5 is a good sounding car from the factory. However, it's nothing compared to the S63tu engine with catless downpipes. The sound is absolutely brutal. We don't think it's overly loud as long as you leave the mufflers in place. However, some may find the sounds to be a little overkill for a daily driver.
That said, the F90 M5 with the S63 engine actually has 4 total downpipes. There are the primary and secondary downpipes. As such, you can choose to just go with the primary or secondary. This will leave 2 of the cats in place and keep the sounds a little more modest. However, the performance and power gains will also be a bit lower compared to doing fully catless.
Best F90 M5 Upgraded Downpipes
Alright. It's time to dive into a few of what we believe to be the best M5 downpipes around. Please note - this is not an exhaustive list. Rather, the below are a few of the F90 S63 engine downpipes we believe offer the best balance of price, quality, and performance.
1) F90 M5 VRSF Catless Downpipes
If you're committed to buying catless downpipes then stop reading and go buy these VRSF F90 downpipes. Seriously. We write about VRSF products often since it's easy to do so. VRSF offers an excellent balance of price, quality, and performance. All of our BMW's run tons of VRSF bolt-on mods with great success.
Their F90 M5 DP's are made from stainless steel and come with a LIFETIME WARRANTY for fitment and defects. Now, consider the price point is $599 each for the primary and secondary pipes. Combine the two and the price all in is $1,099.99. Most S63 F90 options come in at $1,500+.
Point is - we believe these downpipes offer top-notch quality at prices that are unmatched. We run VRSF bolt-ons for a reason and are confident they're the best all around option for the BMW M5, too.
Price: $599.99 each, or $1,099.99 for primary & secondary
Buy Here: F90 M5 VRSF Catless DP's
2) RK Tunes F90 M5 Catless DP's
RK Tunes catless downpipes for the BMW F90 M5 are pretty similar to the above VRSF option. They've done some great work in the BMW aftermarket scene. RK Tunes DP's are also among the cheaper options for the M5 S63 engine.
However, they do still come in at $800 each or $1,500 for the set of primary and secondary downpipes. We suspect they're very similar quality and performance to the VRSF option above - just at a slightly higher price. That's why we like the VRSF catless DP's so much. Nonetheless, RK Tunes is a solid option for those who are willing to spend more for the same quality.
Price: $800 each, or $1,500 for primary & secondary
Buy Here: BMW M5 RK Tunes F90 Catless Downpipes
BMW F90 S63TU Downpipes Summary
The S63tu4 found in the 2018-2021 F90 M5 is an excellent engine. It offers great performance from the factory, but leaves even more on the table. A set of catless downpipes is among the best mods to take the F90 M5 to the next level. Expect power gains of 30+whp and 40+wtq. Excellent gains for a simple, direct bolt-on mod for the S63 engine. You'll also notice quicker turbo spool and an awesome deep, aggressive exhaust note.
There are plenty of F90 M5 upgraded DP's out there. However, we believe the VRSF F90 catless downpipes offer the ultimate balance of price, quality, and performance. They would be our top choice for M5 downpipes without question. RK Tunes also offers a solid option that comes in about $400 more expensive. Believe it or not, they're on the lower-end of the price range too as some F90 downpipes run $2,000+. We'll take the stainless steel VRSF option at $1,099 with a lifetime warranty.