Or vice versa...

I have an 03 TL. Just crossed 162k and the tranny fluid is pretty dark. Probably gonna get a rebuild, but thats not here yet. I might go 3G. But now I'm looking at coilovers for my 2G bc she runs fine. Just changed the 3rd and 4th clutch pressure switches so I probably got some time. Anyways, the main question is can I purchase coilovers for my 2G that will work on a 3G, or coilovers for a 3G that I can jam onto my 2G. I did some research but only found threads on honda accord coilovers onto the TL. In doing that I read something about changing the top hats? I already asked my friend and he said yeah, but I'd like to know how I can do this and which one to buy. Is spring rate an issue?