BU champ won't work with Roop around, unless we capitalise on it's advantages there is no point of using it over Roop(DP's hax is nice for setting up, but that alone won't beat the advantages of Mach Punch). And this is it's better SpDef:
Machamp@Leftovers Adamant
Hp 252, SpDef 252, 4 Att
-Dynamic Punch
-Stone Edge/Payback
-Bullet Punch/Payback
-Bulk Up
Defensive BU, abusing never missing DP and SE, with good Special Defense able to take even STAB Psychics. Payback is an option since it's easier to stay in on those you'd hit with it, thanks to the SpDef investment. SpDef EVs can be geared to take hits from specific hits and the leftovers can be put into attack.
Guts Champ is one of the mons who beats Nattorei/Burungeru combo alone, though only if it runs Payback which is harder to pull of with the damage from Burn racking up. Main reason to use over Roop is the better SpDef, which allows it to beat Burungeru easier, forcing it out easier.
Fire Punch is not needed at all, only Scizor and Forretress are hit harder than by Dynamic Punch, both Nattorei and Skarmory are hit for the same damage by Dynamic Punch as Fire Punch.
Lead Champ while still nice, is much harder to pull off, since team preview exists, the advantage of it though is that lead champ can easily work outside of the lead position, so it still works, though Lum Berry is a questionable choice now, and can be replaced with either leftovers or Life orb depending on the team.
Machamp@Leftovers Adamant
Hp 252, SpDef 252, 4 Att
-Dynamic Punch
-Stone Edge/Payback
-Bullet Punch/Payback
-Bulk Up
Defensive BU, abusing never missing DP and SE, with good Special Defense able to take even STAB Psychics. Payback is an option since it's easier to stay in on those you'd hit with it, thanks to the SpDef investment. SpDef EVs can be geared to take hits from specific hits and the leftovers can be put into attack.
Guts Champ is one of the mons who beats Nattorei/Burungeru combo alone, though only if it runs Payback which is harder to pull of with the damage from Burn racking up. Main reason to use over Roop is the better SpDef, which allows it to beat Burungeru easier, forcing it out easier.
Fire Punch is not needed at all, only Scizor and Forretress are hit harder than by Dynamic Punch, both Nattorei and Skarmory are hit for the same damage by Dynamic Punch as Fire Punch.
Lead Champ while still nice, is much harder to pull off, since team preview exists, the advantage of it though is that lead champ can easily work outside of the lead position, so it still works, though Lum Berry is a questionable choice now, and can be replaced with either leftovers or Life orb depending on the team.