We recently just saw two very different E30 M3 builds that both used Toyota 2JZ engines, which are beloved for their immense tuning potential. This E30 M3 has an engine swap as well but this time it stays within the BMW M family. It also gains six more cylinders because its owner decided to shoehorn an S85 V10 engine, from an E60 M5, into the E30 M3’s tiny engine bay.

The S85 V10 is a fan-favorite engine. Not only is it a 5.0-liter naturally aspirated V10 that makes 500 horsepower but it revs to 8,250 rpm and makes the most delicious noises. It’s a big old motor, thanks to packing ten cylinders and five liters of displacement, but it’s a relatively lightweight engine for its size. So while it’s certainly heavier than the M3’s original 2.3-liter four-cylinder S14 engine, it shouldn’t be too bad. Though, having 300 horsepower more than the original car more than makes up for its added weight.

It actually fits in the E30 M3 surprisingly well. Remember, a V10 is longitudinally a bit shorter than a straight-six (two banks of five cylinders) and the E30 came with several different straight-six options. So the V10 actually sits in the engine bay rather nicely. Plus, the center of gravity of the V10 is surprisingly low, which means that the added weight doesn’t have as much of a detriment to its handling as you might imagine. All while gaining far more power in such a light car. According to the owner, the weight distribution is 56/44, front-to-rear, which isn’t bad at all considering its engine is literally 2.7 liters and six-cylinders  larger than before.

Paired to that monster V10 is a six-speed manual from an E90 M3, which makes sense as the M3’s S65 V8 engine is extremely mechanically similar to the S85 V10, so their transmissions are probably interchangeable.

What I like best about this build is that its owner decided to build it for both the street and the track. It isn’t just a pure track-day weapon but instead can also be daily driven, which makes it even more impressive. Speaking of daily drivability, the Australian owner bought the car from New Zealand and it was already converted from left to right-hand drive. He also swapped out the original seats for Recaros, which fixed the ’80s driving position. It’s a comprehensively built E30 M3 that looks OEM+ but actually packs a very powerful surprise under its hood.