A comparison of the 91 & 97 front lamps, the inner main beam (high beam) lamps on the 97 front are slightly narrower and less regular in shape being more elliptical, as you can see the nose cone shape lines run much closer to the inner lamps on the 97 causing the lamps to be a different shape.

The outer headlamps on the top picture are actually off a 96 car and fitted perfect in the 97 front which was grafted onto a 96 body by Mongoose (Richard Thomson LSOC) after a brake drum from an artic trailer (semi trailer) shattered and a large piece weighing about thirty pounds crashed into the front of his car on the motorway at 70mph.

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Removing Nosecone (front bumper cover)