In my gen 2 P-07's I have run:
Factory captured recoil spring on polymer guide rod x 2
Factory de-captured blue recoil spring out of a DUTY model, on a CGW SS guide rod, in a DUTY slide
Captured SS guide rods from SSGuiderods.com x 2
CGW SS guiderods with CGW 18 lb springs x 2
CGW SS guiderods with CGW 15 lb springs x 2
Rhino titanium alloy guide rods with CGW 18 lb springs x 2
Never had any malfunctions out of any of those combinations. In the end, for a carry pistol that I live fire practice with fairly often, what I want is a guide rod and recoil spring combo that:
1. works (all of them, in my guns, with my ammo)
2. is as durable as possible (probably the titanium ones, followed by the steel)
3. is as light as possible (polymer, followed by titanium)
4. makes the spring easy to clean (any guide rod that runs an uncaptured spring)
5. can withstand harsh chemicals like acetone and brake cleaner (titanium and steel)
So in the end I sold off my factory and SSGuiderods.com captured springs, and use CGW steel and Rhino titanium guide rods, with uncaptured 18 lb CGW springs. Normally I carry the titanium guide rods. If I was trying to mitigate recoil, I might put in a steel one. I thought about ordering a polymer one from the CZ-USA store for 5 bucks, which is the lightest option for an uncaptured spring, but then I wouldn't be able to throw it in a pan with steel parts and hose it down with brake cleaner. I already accommodate my polymer frames with adhesive Talon grips in my cleaning routine, and wouldn't like to add a part to the slide assembly that can't take the same chemicals I use on the remainder of the slide. There's also no way it can be as physically durable as the steel or titanium ones. Polymer is probably better for captured springs you are going to throw away after 5K rounds or so, not guide rods you are going to run with uncaptured springs for tens of thousands of rounds.
