Springs are springs. As long as they are the diameter, rate and length are what you need, they'll work.

FYI, you can get good coilover springs cheaper than that:
H&R for $67.50 ea

Or, if you're building something that can take a longer spring (like 10"+), dirt track stuff is cheap:
QA1 springs for $39.95

Shop around. Most spring sellers websites aren't well optimized, you'll have to get creative with your Google searches to find them. Search for things like "2.5 race spring" or "2.5 track spring", "coilover spring" won't always find them.