René Stam’s 445bhp S65 V8 1999 BMW Z3 Roadster E36/7

While Readers’ Cars submissions normally land in our inbox, we spotted this car on a forum, and it was too awesome a machine for us to not give it some page space here in Total BMW. What you’re looking at is a Z3 Roadster that has been transformed into a snarling, V8-powered beast, and it’s the creation of Dutch enthusiast René Stam.

Built over four years from 2015 to 2019, René’s Z3 is an absolutely awesome machine, and the amount of work that’s gone into it is astonishing. The engine is from a 2009 E92 M3 that had covered just under 53,000 miles, while the six-speed manual gearbox is from a 2010 car that had just over 21k miles on the clock. Naturally, René has not left things alone under the bonnet, with the S65 receiving uprated crank bearings, uprated spark plugs, a custom exhaust system incorporating four sport cats, as well as a fully programmable standalone ECU.

However, perhaps most impressive of all is the work that was carried out to enable the S65 to actually fit under the Z3’s bonnet. The large intake plenum was simply too tall to squeeze beneath it, and the velocity stacks meant that it wasn’t simply a case of fitting a flatter plenum, so René had custom stacks machined to fit under the custom intake plenum, which is some awesome engineering.

And with 445hp to play with in the lightweight Z3 Roaster body, the result is explosive performance. “My S65 Z3 weighs 1345kg with a full tank of fuel, and almost empty, the car weighs 1285kg, which is 500kg less than the E93 M3 V8 Convertible and 300-400kg lighter than the E90/2 M3. The S65 Z3 is also much faster and light-footed with a nice balance,” smiles René. “My S65 Z3 has over 120hp more than a Z3 M and is much faster to 100km/h, and is also derestricted, so has a top speed far above the usual limited 250km/h,” he adds with a grin. “My S65 Z3 is also lighter than a standard Z3 M (which I also had) and has better weight distribution, and, wow, that sound! Really a super V8 sound,” enthuses René.

Of course, there’s a lot more to this build than just that S65 and the performance it delivers, and René has put a huge amount of work in across the whole build. The Z3 sits on BC Racing coilovers with adjustable camber plates, and he’s refreshed the suspension, fitting new wishbones and rods and Strongflex poly bushes throughout. A KSport BBK delivers serious stopping power, with stainless brake lines and an M brake booster, while 18” wheels fill out the arches to perfection, and the concave rears wear meaty 265-section rubber.

The Oxford green exterior has largely been left standard, aside from the addition of a front splitter, which makes this Z3 something of a sleeper, while the tan roof matches the fully retrimmed interior. The whole cabin, from the dashboard to the doors, has been covered in leather, while the centre console, which houses some custom-mounted gauges, has been trimmed in Alcantara, as has the handbrake handle. The gear lever and handbrake gaiters have been finished with M tricolour stitching, and the steering wheel has been retrimmed, complete with perforated grips, and René has also added a set of alloy pedals. Last but not least, you’ve got those single- piece Corbeau bucket seats, the perfect centrepiece.

We’re just scratching the surface of this build and how much work has gone into it, and it’s a seriously special car. “I had the car largely built by a BMW motorsport specialist in his spare, less valuable hours, minus my 100s of hours that went into it. Most of it is new, and several parts have been custom-made for this special build,” René explains, and that gives you an idea of just how much of a labour of love this Z3 was. And while René has had an amazing time with his epic V8-powered roadster, it is now up for sale. “It’s time for someone else to step in and enjoy so that I can continue with the next project in the long term,” he says, and if we had the €60,000 he’s asking for it, we’d be on the next flight over to The Netherlands. It’s advertised on both AutoWereld.nl and the Car & Classic website, with loads more pictures and details, so if it floats your boat and you’ve got the funds to make this hardcore soft-top yours, make sure you check it out.