If you replace D60 A2s with X1s, your mileage may improve, and you may have quieter, longer last tires, but cornering performance and sportiness will suffer quite a bit.

X1s are not H-rated performance tires, Dunlop D60 A2s are.

Kerry

99 SVT Contour Silver Frost, #365/2760
91 Isuzu Impulse XS Kammback, Handling By Lotus
Victoria, BC, Canada