Sharks have been in excellent form of late but sit in 13th spot in the table while Glasgow have their eyes on a top-two finish and home semi-final.
"I said to everyone else that you can probably get rid of their start of season form now," McDowall told the BBC Scotland website.
"Everyone knows that they've grown into the team that we all thought they were going to be this season.
"All their Springboks are back fully fit and rested from the World Cup. We know how dangerous they are. It's one loose kick and then you're under your own posts.
"We know the X-Factor they've got out wide and also the dominance they're providing up front."
Last week, Warriors confirmed the return of Adam Hastings from Gloucester for next season and McDowall reckons his fellow Scotland international's experience in the English Premiership will be invaluable.
"He's a good friend of mine and an unbelievably talented player as well," he added.
"The whole squad's really excited to have someone of his calibre back in and really add to us.
"Everything that he'll have learned and taken away from playing at Gloucester, he'll be able to bring back here, playing a different style of rugby in the Premiership.
"We know he's the type of player that fits our game-plan perfectly and the way we want to play."