G30 M550i or 540i? Real-world ownership experience after 2 years – let’s compare note

[Grenier]

I’ve been daily driving a 2019 G30 M550i xDrive for the past 2+ years (now at 48k miles) and I’m seriously considering trading it in for a clean low-mile 540i.

The M550i is an absolute monster – that B58 with the tune I put on it (pure stage 1) is stupid fun, launches like a rocket, and the sound with the active exhaust is addictive. But fuel economy is brutal in the city (I’m averaging 14-16 mpg mixed), maintenance costs are starting to creep up (just did plugs + coils), and the insurance is noticeably higher.

The 540i seems like the smarter daily: better mpg (22-25 mixed from what I’ve seen), similar comfort, still plenty quick with a tune, and cheaper to run long-term.

Those of you who have owned both or switched from the 550i/540i – what’s your honest take?
- Did you regret going down to the 540i?
- Is the power difference really that noticeable day-to-day?
- Any major reliability differences I should know about on the G30 platform?

Also open to hearing from people who went the other way (540i → M550i).

Bonus: anyone running a JB4 or Bootmod3 on the B58 in a G30? How’s the drivability?

Looking forward to your experiences – this community always has the best real-world info.

Cheers!

[Phillies8008]

I think a lot of the equation boils down to how you're going to be able to use the car the majority of the time. If 95% of the driving you'll be doing in it is around town and on the highway, and your chances to really hit a fun road, etc. are going to be very limited, what's the point in paying more for something you can't use, both in up front cost and ongoing costs?

For me, a monster of a daily driver would be largely wasted. On a daily basis I pretty much just drive four-lane roads that are typically too crowded to do much of anything resembling fun and are too boring to make it worthwhile anyway, and stretches of highway that are also frequently fairly crowded, etc. On a typical day the most exciting thing I get to do it accelerate down an on-ramp, and even then 75% of the time there's some moron in front of me who wants to merge onto a highway at 45mph. I'd much rather put the money into a fun weekend car or two for when I can let it loose a little bit, and that can be tailored expressly for fun without any other considerations that a daily driver is necessarily going to entail.

Depending on what you get it may not end up being cheaper to acquire, but the upkeep costs will be less since you're driving it far fewer miles than you otherwise would, the fuel efficiency is less of a concern for the same reason, and depending on what car you're talking about insurance can be dramatically cheaper than a daily driver, especially if you can go with an enthusiast-focused insurer like Hagerty.

[erickonphoenix]

Kind of surprised you haven't included the M340i. It kind of does M550i things on a 540 budget even if there's less theater.

I didn't think the 5 series was appreciable more roomy compared to the 3 series but I'm smaller than average.

[ppointer]

I think you would know better than I -- doesn't your M550i have the N63 V8? The B58 is what my '22 540i has.

Anyway, I am very happy with this car. It has all of the power I need or want, which is saying something for the Grand Prix that is South FL. Sounds great at any throttle location. MPG's have averaged 28.6 for 30k miles, according to my Fuelly account. Around town is about 24. Have gotten low 30's on long trips, with 34.3 the highest with the cruise set on 82mph. Only advice I have is try to avoid the m-sport brakes -- they suck.