[motion]

In the past, Ferrari used the spelling "spyder". Now, they're using "spider". Lamborghini continues to use "spyder".

From Wikipedia:

GTS ("Gran Turismo Spyder") in older models, are open Spyders (spelt "y"), or convertibles (see 365 GTS/4); however, in more recent models, this suffix is used for targa top models (see Dino 246 GTS, and F355 GTS; the exception being the 348 TS, which is the only targa named differently). The convertible models now use the suffix "Spider" (spelt "i") (see F355 Spider, and 360 Spider).

Seems like a marketing preference to me, but not really sure.