Not sure if I'd necessarily say dramatic effect, but definitely got what I wanted and expected. My favorite swaps:
EMG GZR on my Highway One P bass - exactly what I wanted a P bass to sound like. Extra points for getting rid of the useless (to me) Greasebucket wiring along with the pup upgrade. My favorite P bass pickup, works wonders with La Bella flats that I have on it. I've had a few P basses and P bass pickups, this one has the best mids and sounds wonderfully vintage.
Norstrand MM4.2 on my Stingray - had this baby in 2 different Stingrays. First time I paired it with a John East MMSR preamp (switched out the original 3 band preamp) and it delivered the vintage Stingray tone fantastically - instant Sade tone. I now have it paired with the original Stingray 2 band preamp and it works just as well, but I'm favoring this one more because 2 band ray preamp is my favorite bass preamp. I wouldn't say the tonal difference is drastic (I didn't want it to be!), but it definitely has less clank, nicer low mids and lows and sounds a bit smoother - sounds like a 70s Stingray to me. One important thing is the stagger design on it - pole pieces have less of a stagger that fits both my setup better, and the modern Stingray 11" radius, and is just more comfortable to play over.