It's popular opinion that Spohn SFCs are the best. They look like they're better built and thought out, so I'd like to get some. I'm wondering if I have to modify anything on the car to install them since I've heard some SFCs require something done to the springs. I also have dual cats, am I going to have to change anything there as well? Do you weld the whole length of the rail, or are there better spots than others to weld them. My chassis guy is going to weld them up, but I'd like an opinion from the people who designed them.

--Hotchkis strut tower brace & Energy suspension bushing kit going on this weekend... woo!

 

I got the Spohn sub frame connectors and did not have to do anything except weld them in. As long as you get the dual cat version of his SFC's you should be ok. As for welding down the rail, I welded mine in with 1 inch welds about every 6 inchs apart the entire length of the rail.