Chikenears had the Roush kits on sale, but it's over now -
http://www.f150online.com/forums/showthread.php?s=&threadid=181045&highlight=roush
PM me and I'll let you know where to find good prices on the Hotchkis parts.
Here's a good thread about the differences between the Roush and the Hotchkis kits -
http://www.f150online.com/forums/showthread.php?s=&threadid=174693&highlight=roush
The best deal would be to replace all springs, shocks, and to get stiffer anti-sway bars. The Roush kit includes all new springs and specially-valved Bilstein shocks all around. The Hotchkis "TVS" kit includes all new springs and two new anti-sway bars. They also sell specially-valved Bilsteins. Or you can go with the most popular, QA-1 adjustible shocks. You sort of have to decide how much you want to do all at once, since the kits have different parts in them. And like I said, Ruslow also makes coils. Hellwig makes nice anti-sway bars too.
I didn't necessarily mean that the Ruslow springs were BETTER than the Roush, but different. Better for autocross, yes. Worse for a smooth ride. Roush made a very well balanced kit (after all, they're the ones who designed the Lightning suspension for Ford). But if you want added stiffness for performance, then yes, you should buy Ruslow's springs.
For comparison, I believe that the stock springs are rated around 600 lbs (meaning it takes 600 lbs to compress the spring 1"). Roush keeps their spring ratings private, but they're said to be slightly softer than the new revised Hotchkis springs, which are a 960 lb spring. Ruslow sells any spring you want, from 750 lbs to 1500 lbs. Most popular are his 1000 lb coils.
So, you have to decide what you're going for. My plans for my L are Ruslow 1000-lb coils, the Hotchkis leafs, QA1 12-way adjustible shocks all around, and Hellwig anti-sway bars. I guess the good thing about coils are that they're cheap, so if it's too stiff for me, I can swap them.
Here's Ruslow's page on nloc.
NLOC Ruslow SV Page But, to find out the best info on his springs, just do a search on nloc instead -
Search
Here's his website too, but it doesn't have much info. He sort of just does this on the side.
Ruslow
If you're seriously considering new suspension work, you really have to read the GURU's site. It's probably the BEST source of information on Lightning autocross performance:
Tim Skelton's Website