I bought a SD9VE from Bud's ($275), ordered a spring kit and a trigger from Apex Tactical ($60), and ordered a take-down plate from NDZ ($12). The gun arrives tomorrow, and the parts will be here soon.
The new SD9VE joins my old SD9 (black slide). The old SD9 has a Trijicon night sight on the front and a Galloway 17 lbs recoil spring. The trigger (unaltered) on the SD9 is smooth, fairly long, but really pretty good.
My goal is to move the SD9 black slide to the new SD9VE frame, after adding the Apex trigger and spring, plus NDZ take-down plate to the frame; and the striker block spring to the black slide (I'm not sure I am going to use the Apex lightened striker spring, since reliability is everything with a self defense pistol).
I will also modify the striker blocks of both frames, turning them on a dremel tool to round the shoulders like on the Apex Universal Striker Block or the Burwell trigger job for M&P's. The trigger bar will get a little polishing on the new frame (the old SD9's trigger bar has already been polished). [For people who want to improve the trigger of their SD's, these are two no-cost avenues to pursue].
The Galloway recoil spring will probably move with the black slide. I may swap the new barrel (stainless steel "in the white") to the black slide -- all based on the premise that parts are totally interchangeable between the SD9 and the SD9VE. I also assume that the new frame, with Apex parts, will have a better trigger than the old SD9 frame -- an idea which is not proven yet.
This will give me two SD9/SD9VE pistols, one all black and one two-tone. Both will be close to perfect if all works out.
Eventually, the stainless steel ("in the white") slide of the SD9VE might go out for a black or dark grey Cerakote finish -- for an additional cost of ~$75. The rear sight (plastic) on the SD9VE slide may be replaced by a M&P rear sight I have in my parts box, assuming it will fit (it is missing the set screw, but I wrote to S&W to ask for one, and they typically send small parts like that for free, being the great customer service organization that they are). I may order a 20 lbs Galloway recoil spring ($30) to see how it works compared to the stock spring in the new SD9VE.
If all that makes sense - I am going to have two 9mm SD's, with two different personalities, one for the home (two tone) and one for occasional carry (most typically for hiking and fishing; the J frames are more for urban pocket carry). And a lot of fun doing all of this in my garage "shop" over the next week or so.