Complex sentence: During her time in XPW, she took part in an "invasion" of Extreme Championship Wrestling's "HeatWave 2000" PPV, wherein several XPW wrestlers attended the ECW event and and an altercation ensued between the two promotion's rosters.
Split into simpler sentences: During her time in XPW, she was present at an incident which took place at Extreme Championship Wrestling's "HeatWave 2000" PPV. Several XPW wrestlers attended the ECW event and and an altercation ensued between the two promotion's rosters.