I bought one this summer to put on my Formula 350. Interestingly, my TTA has 17k but the original spoiler looks brand new. The Formula has 20k and the spoiler looked like it had spent it's life in the woods.
Anyway, there are a couple of posts about the spoiler, prep and install - search them. The spoiler is NOT PAINT READY SMOOTH. You could try it but if your car is nice, you'll be disappointed. There were plenty of rough spots and the edges didn't match up on both sides. My paint guy only charged me $100 to paint the spoiler but it cost me about 5 hours ($250) in prep work. If you're not finicky, you could probably get away with a resand and reprime...but I'm picky. If your paint on your car is nice, the spoiler better match.
Don't try to use the stock window rail mounts. I did what some of the threads suggested and loosely mounted the wing (before paint) on the two rear bolts. Marked 2-3 spots on each side where the wing touched the "lollipop" shaped brackets from the original window rail mounts and threaded in some high quality stainless flat head screws (shorter ones toward the front as the wing is MUCH thinner there - be careful). Match up the hole for the screw with a spot about 1/2 - 3/4 up the "lollipop" in the bracket....so you can slide the window rails in together on all sides and then be lined up with the rear bolts....Once you take the old one off, you'll see what I mean.
Makes all the difference in the world on the car. Can't tell it's a replacement - only a tap/squeeze will let you in on the difference.
Also, removed and had the third brake light assy painted with the spoiler. The "new" paint of the spoiler doesn't contrast with the car but seemed to stand out against the faded light assembly.
BTW - shipping was the biggest expense!! - I think it cost me nearly $200.
