Suggestions on tires?

[NardoW12]

I have a 2004 X5 3.0i with the Sport Packages' 18 inches wheels
I had been running around 30K miles with the tires it came with and it wearing out pretty bad now...
so I was thinking about putting some new tires on soon(at least for the front ones since they are about to pop like every second...lol)

The stock ones were Michelin Energy MXV4 Plus (255/55R-18, Speed Rating HR)

I'm thinking about buying tires that have VR or ZR Speed Ratings..
so for you guys who bought or tried those VR or ZR tires on X5, how much difference does it make? and any suggestion on some performance tires that would fit on the stock wheels I have? Thanks!