My only mod right now is HKS DLI, Evo 9 Turbo and 3'' Cutout with Tune
I already purchased a set of GSC S2 Cams, HKS Cam Gears and ARP L19 Headstuds for my Evo 8.
I want to rev 8K without any problems.

Which springs/retainers should I go with??
Cosworth? HKS? GSC Beehive? Ferrea?

Also which valves do you recommend?

 

anything??

 

I didn't replace retainers when I did cams and springs. I used MAP beehives. Also, there is no reason to rev to 8000rpm on stock turbo, peak power is before 7000rpm

 

Same here I just replaced the spring's with Map Beehive's and I'm running kelford 272's

 

I'm doing a full Ferrea valve train with beehive springs and GSC S2 cams but I also plan on running an ETS FP HTA3582R in the future so planning ahead.

I've heard these springs can rev to 10,000RPM but don't quote me on that.

 

Kiggley is the best, but overkill for only 8k rpms. I use Brian Crower Springs/titanium retainers and rev to 8600 rpm no issues.

 

do you guys know who makes map beehives springs?

 

you got the single 95# springs ?

 

A1 Technologies is what my box says

 

That sounds right. 95lbs of preload.

 

I would go with the GSC beehive springs, why not you have the cams already. I used this exact set up and I haven't looked back.

Bryan

 

I use the BC Springs/Retainers with S2s. Never had any issues.

 

I personally use the GSC stage 3 springs and retainers.

 

I guess I will be going with the MAP Beehive Springs and MAP Valves and keep the stock retainers

Should I get a port polish done on the head? (stock size valves) Would it make a big difference on stock 9 turbo?

 

You'll make more power on less boost. Until you get a turbo capable of pushing more air, you may not see too many gains.