Hi anyone know the difference between the red prodrive springs and the Eibach pro kit ? Did abit of searching tho never came up with much ,folk saying Eibach make them both , what is the better out the two ?

 

There were 4 red Prodrive spring sets - what car?

 

Forgot to say it's for my mates Hawkeye he's got standard black springs on just now

 

I assume he's got an sti if you are looking at the red Prodrive springs?
For the Hawkeye sti, the Eibach's were very similar rates to the Prodrive S05. The Eibach's were 7mm lower at the front, and too low at the rear.
The Prodrive S05 sti springs also came with shorter front bump stops.
If you change to lower springs you should the bump stops - they are inside the strut housing of an sti inverted strut.

 

Yeah it's an sti ,did they only change the front bump stops ?

 

Yes, the Prodrive rears hardly lowered at all, which is good for positive chassis rake.
However, if you change to a stiffer rear stop, as well, you can further reduce understeer. That is what I do with the Eibach WA/A2+A3 springs - which are linear and 5% stiffer at the front, than either the pro-kit or the Prodrive.

 

what was the spring rates on the RB320 in comparison to red prodrive sti springs?

 

Same spring rates compared to S05. 41N/mm, 39N/mm.
Different ride heights and gc base coil spring diameter, at the rear, on RB320.