I agree with your friend bradyroker. You should probably replace all four struts.

So it looks like you're going to need the rears too. Well, here's a pair of rears like the ones I had installed on my '00 Millenia just a couple of months ago Buy Sensen Rear Pair Shocks & Struts for 1997-2000 Mazda Millenia, Lifetime Warranty | 3212-0274, 3212-0274,341259, 72454. They should also match your '98.

Now I couldn't locate a pair of fronts. Perhaps I overlooked them. But check behind me. Let me know what you find out.