The record assembled here is a working bibliography for the Esprit X180R — the period magazine coverage, factory paperwork, LotuSport race reports, and press releases that underpin the rest of this site, together with the small shelf of books that touch the car. Where an item survives only as a scan or an online archive, the link points to it directly. Corrections and additions are welcome.

The X180R was one answer among several to the era’s homologation rulebooks. Set beside them — the year each was built, whether it was road-legal and fully caged as sold, and where — the X180R’s distinction is narrow but real: it is the last car here sold new and street-licensable in America with a full chassis-integrated cage. (The Japan-market Carrera RS Clubsport was caged and road-legal too, but sold in Japan, in 1992.)
| Car | Year | Built | Series | Road-legal as sold | Full cage as sold | Disposition |
|---|---|---|---|---|---|---|
| Lotus Esprit X180R | 1991 | 20 | IMSA Bridgestone Supercar Championship | Yes | Yes | All 20 accounted for in the registry; road-registered ever since. |
| Porsche 964 Turbo S2 | 1992 | 20 | IMSA Supercar (USA only) | Yes | No | |
| Porsche 964 Carrera Cup | 1992–93 | 45 | Porsche Carrera Cup | Yes | Converted back to road cars before sale to customers when the racing series was canceled. | |
| Porsche 964 Carrera RS N/GT Clubsport (Japan C08) | 1992 | 20 | Group N/GT (Japan, canceled) | Yes | Yes | Partially converted back to road cars in Japan; FIA roll cages retained, covered in hand-stitched leather. All 20 delivered in unique colors. |
| Ferrari 348 GT Competizione | 1994 | 50 | Ferrari 348 Challenge | 50 road-derived cars plus 13 dedicated race cars (11 Michelotti, 2 GTC/LM). | ||
| Ferrari 355 Challenge | 1995 | Ferrari Challenge | Yes | No | Street cars converted to race cars by dealers using a factory kit; a few later built by the factory itself. | |
| Porsche 911 Cup 3.8 (993) | 1994–98 | 127 | Porsche Carrera Cup / Supercup | 15 of the 127 built in 1998. | ||
| Lamborghini Diablo GT2 | 1998 | GT2 | No | Full race car, not offered as a road-legal conversion. | ||
| Lamborghini Diablo GTR | 1999 | 80 | Diablo GT-R one-make series | 6.0-liter V12. |
blank — not recorded in any source held; never guessed.