If there is validity to this, it's embarrassing, IMO.
At the risk of perhaps being naïve, I'm going to respectfully disagree. I think that the return of an inline 6 in a Lexus, even if it's Mazda-sourced, is an exciting and very positive development. With some exceptions, Mazdas tend to be fairly reliable (my nearly 12-year-old Miata can vouch for that), and if Mazda decided to join 1.5 of their 2-liter 4-cylinder Skyactiv-X engines to create a 3-liter inline-6, whereas Toyota refused to do this with either their 8AR-FTS or M20A-FKS engines, then more power to Mazda.
I think you're going to see a lot more of this sharing in the next 10 years. Nobody knows exactly how electrification will go, but spending the money developing new engines and platforms is going to look increasingly like buggy whip manufacturing to the bean counters.
The number of internally developed RWD products seems to be dropping. Losing GS, and the IS and RC theoretically being on a Mazda platform leaves only LS and LC for a true proprietary RWD platform - even adding LQ is going to be relatively low volume...
It seems like the investment in RWD is becoming increasingly "niche" at Lexus, and Toyota doesn't have a strong history of supporting products with low volume and significant R&D expenditures.
While Mazda has been quite clear about their upcoming Skyactiv-X inline-6, there are far less specifics about their RWD-centric Large Architecture. What if they're simply borrowing or adapting one of the newest Toyota/Lexus RWD unibody architectures (TNGA-N or GA-L)? That sounds like more of a win-win for the 3 marques.
Not sure why Toyota really bothered with GA-L... it's becoming a niche investment without a GS, mainstream RWD SUV, and the 2RC being based on a Mazda architecture and same for next IS.
Per the
Best Car rumor, 4IS will be on one of the new Toyota/Lexus platforms, be it the Crown's TNGA-N or the LS/LC GA-L. It's 5IS, based on the
Best Car rumors, that would make the eventual move to the Mazda Large Architecture that may well be a variant of TNGA-N or GA-L.
Also, isn't the Crown on "New-N"? Not GA-L? If I'm not mistaken, "New N" dates back to 2006 GS/IS and was updated for 2012 GS/2013 IS.
As noted above, the latest 15th-gen Crown is the first and thus far only vehicle on the TNGA-N architecture. There's no question that TNGA-N and GA-L are closely related, but Toyota is less than forthcoming on the specific differences between the two. I suspect it's mostly a matter of sound insulation, torsional rigidity and the like.
If
Wikipedia is correct, the only "New N" vehicles are Lexus 4GS, 3IS and RC. Older Lexus models and Crown15's predecessors are "Old N".