Part numbers for restoring BCNR33 front wheel arch liners, brake ducts, and undertray

[Super Roo]

So, I'm looking to fix up under the front of my R33 GT-R (1995, not a v-spec or N1). Specifically after seeing the one they had in the Nissan Heritage Collection when I was there on holiday recently (awesome place by the way, if you're in Tokyo you have to go check it out) I want to put the front brake cooling ducts, engine undertray, and the front halves of the front wheel arch liners back in as mine came with none of these things when I bought it. I know there are some clearance issues on the wheel arch liners with 18s and the stock BOV, but I've got some solutions for that so I'm not too worried. What I was hoping for some help with is working out which part to get for the front of the right front wheel arch liner and the engine undertray, as there are two part numbers for each of these.

For the engine tray the numbers are 75890-05U20 and 75890-24U20. The first is the basic part, the second is listed as being for series one v-spec cars and the N1 in all years. I have actually found pictures of the two parts and the only discernible difference is an extra bulge on what I believe is the driver's side of the part. So my question is does anyone know what that bulge is for? Is it going to be useful to have that extra space down the track (for mods etc.) or is it some weird N1 specific thing that I'll never have a use for? I've attached the pictures.

For the wheel arch liners I haven't found any pics. The base part number is 63844-24U00, and the alternate part is 63844-24U10. It sounds like the second part was used for the v-spec and N1 in series one, and the N1 in series two. By series three all variants used the first part. Does anyone know what the difference is?

Thanks heaps to anyone taking the time to read and help, really appreciate all the knowledgeable helpful folks here.