This goes out to Tork Monster, If you can give some info on your lip boot spoiler, might give it a go, nice picture of your car with your DIY job , looks good, found similar on E-bay but not sure if it's like the one you bought or maybe different.

 

Powerhouse-
I just stumbled across your post... sorry I didn't respond earlier.
The photos you posted look like the same type of product I used to make my spoiler. The main criteria is that the piece be solid; not hollow. You need to purchase TWO spoilers and cut them into pieces to make a three-piece spoiler for the tail of the F-Type (coupe). I would suggest getting spoilers that are NOT painted, as you need to cut them and do a lot of sanding. Sometimes painting over paint can have reactions, and could force you to completely sand through the old paint and start over.
I went back to my original post when I first installed this spoiler for better details:

This was a DIY project. I bought two solid rubber spoilers off eBay; I think they were for a Honda Civic. Marked the pieces up to best fit the curves of the car, and cut them (oversize) with a simple box knife.
Test fit, sand, test fit, sand, repeat until they were the right shape & length. I had to heat them up to bend them to the curves of the Jag. Getting the angles was critical, and I spoiled one piece by cutting it at the wrong angle, and it was too short to fix. Good thing there were two spoilers to work with.
After getting them cut and sanded to shape, I sanded all exposed surfaces down to 600-grit.
Spray the parts with an adhesion promoter (I used BullDog).
Spray a few coats of primer- Use a flexible primer, or a flex agent should be used to prevent cracking the paint when you bend the parts into shape; the BullDog works well for that too. Mix at 1/3 BullDog to 2/3 mixed paint.
Sand with 600 grit, including ends. Respray & re-sand any areas that aren't covered with primer.
Paint with color coat. Make sure no runs or holidays exist. Do not sand color coat unless you plan on re-spraying (you will flash the metallic)
Add flex agent to clear & paint ~3-coats of clear. wait 5-10 minutes between coats.
If you are really good and no dust gets in the paint you can skip wet sanding... otherwise wait a few days for the paint to fully cure, then wet sand with 1500, then 2000, ultra fine, etc.
Go through the 4-5 steps of polishing to reach a level, scratch-free shine.

Adhering the parts to the car is pretty simple. Clean both surfaces with a de-greaser or mild solvent (I used denatured alcohol). Use 1" wide Scotch 3M high-strength outdoor mounting tape, adhering to the spoiler first. You only get one chance so make sure the parts are properly in place, and slowly peel the backing off the tape as you stick the parts to the car.

This is a pretty simple project, but getting the parts cut properly and painted without issue is a long tedious, task.

Cost for the spoilers was ~$60 for both. The paint was ~$260. Labor was free





If you are used to doing bodywork & paint, this will be an easy task. It took me forever to get things right, and I had to do a few things over to get rid of flaws, but I have been very pleased with the results.

The fact that you like it enough to want to duplicate the effort is the best compliment I have received on it

 

Thanks for the reply Tork Monster, will give it a go, mine been red with black pack, what you think , paint it gloss black or body color.

 

IMHO, I would go body color. Black may look like you just bought a generic stick-on spoiler from eBay.

.....oh, wait