Yankee,
Yep, thats where i was at when i bought my first shield, the PC had not been released yet. I knew it was coming but got tired of waiting for it to be released from S&W, so i bought the standard 9mm to play with until the PC came out. I can tell you this, it was worth the wait... its an awesome little gun.
Thats about where my trigger is at on my PC9...4-1/2lbs now. My PC started out around 5 to 5-1/2 pounds when i got it, but i can`t leave well enough alone...lol. It is leaps and bounds way better than my other standard shield triggers, night & day better... i think you already found that out when you tried your buddy`s PC shield. VERY smooth crisp trigger, reset is spot on, with audible click. I did adjust the trigger loop a tiny bit upward to take out a touch of trigger pre-travel. If you do this, be VERY cautious not to raise it to far.
If i were you, i would just do the trigger job on your standard and stay with that... i would install the apex sear... that will get you exactly what your looking for. I would keep the OEM trigger spring in the gun. Next, i would round off the blocker plunger and polish it once you`ve file, stoned it, to a more rounded dome shape. This helps the trigger pull tremendously. It will be far smoother thru the full trigger travel. Make sure you clean any roughing out of the blocker bore. Another option is buying the apex plunger... it works great... its cheap enough too. I installed the apex plungers in my other shields...they work awesome.
Unless you really think you need PERFORMANCE CENTER to be stamped on the slide... and the ported slide, the standard shield can become as sweet as the PC shield, without the ported barrel. The ported barrel, i dont think its really needed. It dirtys up the inside of the gun a bit. I wipe a film of vaseline in the slide when i shoot it on my gun range alot. This makes it easier to clean the slide after a days worth of shooting. The residue wont stick to the slide when you wipe some vaseline in it, but it wont protect the internal components from powder residue. Therfore i`m not a fan of internal porting, and never will be.
The sights on the PC, they are ok, you can surely see better with them over the regular white 3 dot OEM sights, but there are far better sights out there to buy than what the PC`s come with. The XS BigDot sights are a very nice choice.