As stated, lot's of spring options out there, but anybody who has ever used Swift springs know they are pretty much the best you can get. Virtually never sag, are by far the most consistent on spring dynos, and they typically weigh less than all the competition.

Here are some 140 n/mm (~800 lb/in) springs for the rear of my GT3.
Yellow ones are Eibach ERS (for Ohlins), the Orange-ish are Swift. Almost a 1lb difference in spring alone.

Anybody need some brand new 500# / 800# springs, I have an ERS set for sale.

 

Swift springs all day long. Use them on my rally, track and street cars.

 

I used Swift springs on my 996 Turbo. The difference in price is so small it doesn't make sense to use anything less than the best.

Jon

 

Going on the car with the MCS 2 ways in a few weeks!

 

good going there can't go wrong...