rssc you can do it either way you want, but think of it this way:
1. Get the sear first. Run the sear in any number of sub-$1500 clones, including Century arms, Vector or even (shiver) Special Weapons, until you save up the $4500 that an SBR'd HK94 is going to cost ya.
2. Get the SBR'd HK94 first so you have something that at least is genuine HK and looks just like an Mp5. You can sight it in, work out any kinks in the gun, accessorize, and get in marksmanship practice while you save up for your sear.
Now THERE'S a conundrum for ya!
Oh, imho the PDW is much less stable in full auto fire, maybe on semi-auto the accuracy is comparable, but with the folding stock and such a small package it tends to flex and rock back and forth a little bit if you hold the trigger down. The full size Mp5 just sits there, very little recoil (just a gentle push really), and the recoil is straight back, not side to side. If you can, shoot both before spending your $11 grand.
This is me doing nighttime room clearing stuff a couple of years ago, unfortunately in Missouri you can't get suppressors without a class II license unless you're a LEO--this particular gun is a LEO gun.
[img]http://www.imagestation.com/picture/sraid61/p44ad17b581342a41b52d358c642f465e/fc32c003.jpg[/img]