As far as G power, I seriously doubt there was a series 1 bakugan that originally came with a g power of 710... but with SM you never know. I do recall seeing some series 1 starters at TRU a few months ago with unusually high g but nothing over 700 that I remember. At that time I was oblivious to the smaller bakugan, so I had no clue what I was looking at. I'm actually just now getting into the older series 1 and series 2 stuff... lol.
ALL series 1 Bakugan released in the USA are 250-450G in increments of 50. This means no 355G or 440G or anything like that. They kept it simple... 5 G-powers.
However you MAY see Series 2 Boosters and starters disguised as Series 1 just because they had series 1 packaging and cards left over. Dead givaways for "series 2" bakugan were holes in some, higher g's, and of course the 8 actual series 2 bakugan themselves.
By then they were done in G increments of 10, and I do recall the strongest being the 650G Terrorclaw.
as far as being cheaply made, i can never tell with the B1's.. they ALL feel fake to me...
I resent this comment with ever fiber of my Baku-being. Have a nice day.

Okay, jokes aside... I'm serious B2s feel trashy and fake in my opinion... half of them don't even close right and have horrible paint jobs. And all those "safety" holes in them? don't get me started. I almost gave up on Bakugan when I saw them. It's funny how origins can make people opinions so different.