Yeah not a great idea to mix brands on that car!
I am going out on a limb here but are the Dunlops SP sport max rubber? if so throw them in the bin as they are mince on a hatch.
Mixing the tyres is a disaster for any performance cornering.
Check your tyre pressure also can make a big difference too.
On a car your age nothing should be broken
If funds allow & depending on the condition of your tyres i would at least dump the mismatching tyres [i presume 2 dunlops 2 pirelli ] so what ever make has the most tread left buy 2 of the same make.
Get Michelin tyres, tried & tested
For small upgrades to your suspension just per chance I have some items for sale that will also greatly help out on the rear end HERE
I am hoping a dealer never sold you a car with odd tyres!!!