We’d always advise against fitting budget tyres. They may be getting better, but the difference - particularly in the wet - between budgets and premium tyres is still massive.
There is an even worse option, however: mixing premium and budget boots on a single car. Doing so will dangerously imbalance the car, and to demonstrate how that plays out, Jon Benson of Tyre Reviews took to a wet handling circuit with a BMW M2.
Benson first set times on a full set of Continental Sport Contact 6s, before switching the rears to a different pair of premiums in the form of the Michelin Pilot Sport 4S. This made precious little difference to the lap times, although the feel of the car was altered ever so slightly. Mid-range Kumbo tyres on the rear did slow the car down and make it feel less sweet, without making it dangerous.
Finally, budget tyres were fitted on the back, and later the front axle mixed with Continentals at the rear. We’d recommend you watch the full video to see how this plays out, but suffice to say it isn’t pretty…