So sometime in the near future i will be putting in an MLS HG and ARP head bolts and TB. I'm getting a used head to do some of the work before hand.
I have a 99 GS with 160K... and want to put a turbo in(something small T3?) I already have most of the parts, megasquirt, accel 330cc, walbro, FMIC. I have a turbo but its huge(T3-.50 / T4-.83), and will get a different one. I'm only aiming for about 250hp, this is my DD.
Anyway after I get the head milled flat do I need to replace anything like springs or valves? Do I have to replace my piston rings too? Right now my compressions are all near 170. Would it be worth it to do a port/polish myself with a kit? I would like to get some adjustable cam gears too.

Thanks