I have the C3Motorsport Coilovers.
I like everything about them, except the adjustable perch.
I like the Ground control adjustable perch better and may run a #500 spring in the front next season instead of #450
If you send your struts to GroundControl, they will install both the perches and the Swaybar tabs and powercoat them for you, not sure how much it costs though.
I got on the early Group buy on R3V and got it for $1400 shipped. Now i believe they are in the 1500-1550 range + Shipping.
They come with
4- Koni top adjustable
4- Adjustable spring perches
4- Eibach ERS springs 450F/750R
2- Weld on perches
2- M3 Swaybar mounts
2- Vorschlag Camber Plates (Best plates i have used!!)
2-TCKline Rear Shock mounts (with both e30 and e46 inserts)
2- Spanner Wrenches
Overall the kit is very high quality, and the customer service has been great. ill recommend them to anyone!
**But only if you want to change out all of your other worn out suspension parts.**
Because if you are still on the stock suspension and when you get under there and you see how bad everything is, you will want it fixed right.
I paid close to 2500 when it was all said and done.
Other thing i have (and recommend)
-M3 offset bushings (Switching to THR CAB)
-Rear Subframe Bushings
-Rear Control arm bushings
-IE Big Swaybars (on order)
-New Tierods
-New Control arms