dude it's not 1999 anymore, the s2000 was a one-off celebration for honda to flex their guns
no one's gonna build a sports car motor unless you have serious racing programmes like Ferrari or Porsche
this is similar to the 124/MX-5 platform, 99% same chassis, but different powertrains. The MX-5 doesn't really have a bespoke engine (Mazda3), nor does the 124 (Alfa Giulietta)
honestly though, they already have the Supra. Well its luxurious/futuristic....a toned down LFA
tone the LC500 further down with a 6-cyl, make it no frills and call it a day!