ACK!!!! where are all of the Naruto fans?!?!?! the Powerpuff girls are ahead by one!!!! I used to watch the show and although I have no idea what this Z thing is there is no way that Bubbles Blossom and Buttercup got enough new powers that they would stand up to the Rasengan, Sharingan/Chidori, and Sakura's mad Genjutsu skils!!!! Squad 7 hands down!!!
The Powerpuff Girls Z are not stronger than the original Powerpuffs. The PPGZ can still fly, and might have some degree of super-strength, but aside from that, they use the power of their own unique weapons. Blossom(now known as Hyper Blossom) uses a yo-yo, Bubbles(now known as Rolling Bubbles) uses a bubble wand(can use it as a melee weapon, or to trap enemies in indestructible bubbles), and Buttercup(now known as Powered Buttercup) uses a large hammer.
Keep in mind, the PPGZ are not the same characters as the original Powerpuffs. The PPGZ are 3 completely different girls, 13 years old, living in Tokyo City. One day, Professor Ken Kitazawa was experimenting with Chemical Z(a new form of Prof. Utonium's original Chemical X), but a rice cake was accidentally dropped into the concoction. The resulting explosion sent several black and white lights streaming out into the city. 3 of the white lights found their way to 3 girls, Momoko, Miyako, and Kaoru.
The lights gave the girls the power to transform into the superpowered Powerpuff Girls Z. Momoko can change into Hyper Blossom, Miyako can change into Rolling Bubbles, and Kaoru can change into Powered Buttercup. The black lights found their ways to other hosts as well, but that's another story.
Here's a video of the PPGZ's transformations in case you're interested.
YouTube - powerpuff girls z transformation(all)
Sorry about the rant, but I LOOOOOOVE the Powerpuff Girls.
To answer your question though. No, the PPGZ aren't stronger than the original Powerpuffs. However, the original Powerpuffs could completely beat the shit out of Naruto, Sasuke, and Sakura.