You could probably get some type of adaptors... Local dude in NC put black Mustang wheels on his L, using adaptors. The backspacing may be wrong to do the opposite though. I'd like to see it done though, since L rims are so cheap (in the 99-00 yrs)
A 1" adapter (5x4.5 to 5x135mm) with that wheel will make them stick out way too far IMO. Without an adapter those wheels will stick out 37mm more than our stock 17x8 do. With an adapter 62mm more.
Though I kind of like the photoshop of the lightning wheels on that stang.