I would like to know where can I get these, I checked their website and they only have the valve spring sets, inner and outer but I hear there is an inner set that works with type r outer springs that are good for 9500 rpm

 

http://www.inlinefour.com/porsstifinva.html

ive ordered 2 sets of portflows from them

 

thanks. what kind of retainers do you recommend. i have a set of crower titanium retainers 87093, these are NOT the ones designed for stock springs. I wonder if they could work with the portflow/itr combination