Polished Valve Springs?

Looking for some real world experiences with polished valve springs vs unpolished.

My Trick Flow A460 heads use a TFS spring that is a rebranded Manley NexTek.
They are Manley # 221424-16. Manley also has a 221424P-16 with the "P" being the same spring but polished/treated.

What are the advantages of the polished spring and are they worth the price diff? ~$470 polished vs ~$265 for the unpolished. I've had no problems with the regular springs, just plan on replacing them and the lifters this winter for piece of mind. Curious if it's worth it for the higher dollar springs.

Also, anyone advise of any other brand spring part # that would work and might consider.
Specs: 2.00 installed, 1.64' dia double spring. 250 seat/850 open. 1.070 coil bind.
Cam is .831/.779 gross lift

I wouldn't mind bumping up the seat pressure a touch without getting crazy.

you stay with the same spring , looks like you could slip a .060" shim under the spring for a few more lbs.

I used a PAC spring on the idt heads.i dont recall the IH on them after machining.i want to say 2.050 I did'nt do enough checking before i ordered valves so we ended up with "get by"results.i know i used +.050 locks. Check out the PAC's pac-1228 is the #

A response to a similar question, posted by another on another web site.

Fatigue cracks start from sometimes-microscopic discontinuities in a stressed part's surface. The polishing removes many of these, improving durability. It's very possible your supplier is talking about a much more sophisticated process such as REM: http://www.nwsuperfinish.com/

A valve spring set is only as good as the worst spring so, polishing will lessen the chance for one or more having a surface imperfection where fatigue can start.

I have polished in mine they are easir to visually inspect, but that's probly about it as far as advantage.