I plan on replacing the rear 12" or so of the street tail with a custom piece. I retained Kevin Richards from Surfac3D to create the sketches and 3D models.
Key Design Elements
This section outlines the key design elements which are subsequently described in detail.
Unique tail lights: While the tail lights provided in the kit are OEM, I think the car deserves something better. I don't want anything round.
More vents: The engine compartment gets hot and more vents are functional, plus they look cool.
Remove duck tail: A dynamic wing that will be mounted above the tail section. The duck tail conflicts with a wing both aesthetically and functionally.
Fixed diffuser: The diffuser is molded into tail and it provides the mounting points for the hinge. This means that you need to elongate the holes for the exhaust tips to clear. While removable bezels can cover the holes, they are a pain in the ass. If the diffuser is fixed and the exhaust passes through it, there is no need for elongated exit holes or bezels. In addition, the current molded-in diffuser doesn’t appear all that functional when compared to the race tail. Lastly, the diffuser can project out the rear further which will provide more room for the exhaust (the current diffuser clears the ground by less than a quarter of an inch when the tail is in the vertical position). The diffuser could be aluminum, fiberglass or carbon fiber.
Exhaust: The exhaust should exit through the diffuser, ideally with a crossover and a single Lambo-like exhaust tip. I like the external appearance and sound of Peter's exhaust, but I'm thinking of mounting the mufflers low and parallel to the ground.
Hinging: A fixed diffuser requires a custom hinge that mounts to the top of the suspension cross brace. Given that the diffuser is fixed the pivoting piece of the tail will be much lighter.
Show some tire: The tires are hardly visible at all from the rear and I'd like to see a little rubber.
My first attempt was to modify some aftermarket Lambo-like sequential lights from Buddy Club as shown in the video below. I spent a bunch of time cutting them out of the huge casing, designing a 3D printed bezel and making a mold to vacuform a clear lens.
Kevin did some sketches which looked great, but when he saw the light in person he mentioned that the LEDs were pointed in a weird direction, so we powered it up and they were clearly designed to project light 20 degrees different that how they'd be mounted on the SL-C. While they'd look great, I decided that it was dangerous to have the brake lights set up sub optimally. Too bad, as they would have provided me with a completely unique look.
So I spent a lot of time looking for another set of DOT approved tail lights. The challenge was finding something that wasn't round but was flat enough to work with the SL-C... you'll note that most modern tail lights wrap around the side of the car. In the end, I decided to go with C7 lights with the "fang" in the bezel cut off. Kevin did the following sketches 2-8 bases on C7 lights:
I liked the look so I bought a pair. They're a hell of a lot bigger than the Lambo lights so I had my son hold them up to see what they'd look like. In the picture below the bottom of the horizontal blue tape is where the top of the tail will be when the duck tail is removed.
The rendering below is 3D mesh-based rendering based on a 3D scan of someone's SL-C anda cut-and-paste image of the C7 lights. Note that body split line in the spyder was carried over to the tail section resulting in the splitter and tail lights remaining fixed.
I had a C7 light and bezel 3D scanned. In the pictures below you the scans have been incorporated into the 3D mesh. The first picture from the back is bad ass! I'm not as crazy about the profile because the tail now bulges outwards in the middle. This is due to the tail lights which have a slight curve. More space back there is a good thing and I think that the stock tail is too flat in the back. I haven't decided if I like the profile or not...
Below are some exhaust tip renderings. The first one is a stainless aftermarket Lamborghini part that might be able to be modified. Note that some pictures have black tail light bezels whereas others are white. I think I'm going to go with one of the bottom two.