If you can pick out the bean sprouts, do it. They take way less time to cook that the rest of the stuff. It's very important when stir frying to start cooking the longer cooking things first and then add in the quicker cooking things as you go along.
You need to stir fry at HOT HOT HOT and only for about 60 seconds. The bean sprouts will cook in maybe 15 seconds.
Yes, crank up the heat and cook them very quickly... the vegetables should be al dente and still have their bright colours. pick up a piece of snowpea or pepper and test the texture after a minute or so.
I love crunchy veg and always manage to overcook stir-fried veg.
NOW I discovered the trick.
I put the wok on the cooker and turn up the heat to "ferocious" ( that's a bit above maximum!). Walk away and do something else for 10 minutes.
Then I rush back, toss in a little oil, and hurl those veg into the spitting pan. A few deft flicks of the wrist and they're ready.