It’s been widely reported that the current-generation Toyota Supra most likely wouldn’t have happened without assistance from BMW. We’ve now learned the tie-up continued until the very end of the sports car’s life cycle. Introduced last November, the A90 Final Edition was also a collaborative effort between engineers from both automakers, but with a twist.

Sources close to the matter have told us two other companies were involved in the project, one of which operates under the BMW Group umbrella. ALPINA allegedly helped fine-tune the axles for the coupe’s final iteration before the fifth-gen model rides into the sunset. Engineering company Holzer also contributed to the development of the hardcore special version, which is limited to 300 units. The final Supra is available only in Europe and Japan, with production split evenly between the two regions.

We can add another name to the list of companies directly involved in the project. As with the regular Supra, the A90 Final Edition is built by Magna Steyr in Graz, Austria.

There’s still one missing piece of the puzzle: Who worked on the BMW B58 engine? We bring this up because the car uses the most potent iteration of the turbocharged inline-six engine. The 3.0-liter unit is rated at 429 hp and 420 lb-ft (570 Nm). These strong output figures are not found in any BMW-badged model.

We’re not holding our breath for a hotter Z4 to match the Supra A90 Final Edition, but it gives us hope that future BMWs will feature an upgraded six-cylinder engine. We’ve already reported on the possibility of a next-gen 3 Series M350 with 417 hp. If our sources are accurate, it would give the M Performance sedan a 31-hp boost over the current M340i sold in the United States and an extra 48 hp versus the European model.

Meanwhile, the Z4 and Supra are expected to retire next year. Toyota has hinted at keeping the iconic nameplate alive with a next generation, presumably without BMW’s input. Bavaria’s sporty roadster is highly unlikely to spawn a follow-up to the G29. The axe is also about to fall on the 8 Series Convertible, leaving the 4 Series Convertible as the last car with a folding top. However, the future doesn’t look great for the 4er either, since a next-gen model is increasingly unlikely. Nevertheless, an electric cabrio could happen in the upcoming Neue Klasse era.