Body

Jigging dimensions

Differences between Si and GTi

Rear Wheel Arch

Biggest difference [...] is the rear wheel arch. The GTi rear wheel arch is a totally different shape which is hidden by the plastic body trim. Nearly everything else can be transferred over to clone an Si into a GTi. The major give away would be the rear arch though.¹

Tailgate

There are two styles of tailgate mounts;² The hinges are completely different. To swap them, you'd need to cut the hinges off the donor car and weld them to the recipient car:³

• Si are all the same (and are the same as other late 205s);
• early 205 GTis are different

Gutmann body kit

tbc - https://www.aussiefrogs.com/forum/index.php?threads/205-gutmann.21777/