I have a feeling SFGAdv, because they have been adding rides like crazy this year, and will probably continue next year.
1999 3 coasters, 22 other rides, and a new section.
2000 Hurricane Harbor.
2001 Nitro, addition to HH and tons of upcharge attractions.
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Nitro: The Most Explosive Coaster on the Planet explodes at Six Flags Great Adventure in 2001.