During my researches it seemed that the vast majority of coilover setups on 1Gs used softer springs in the rear. 325/200, 375/250, 400/300, 400/350, 500/350, 500/400 and 550/450 were all mentioned. I only found one example where the spring rates were equal: Farzaan Kassam ran 600/600 once. I don't know on what car or when, but 600/600 is way too stiff for a 1G, and if it was on a 2G then it doesn't really apply since 2Gs really need higher spring rates.

OTOH it seemed like the typical lowering spring setup used equal rates. Suspension Techniques springs were supposedly 400/400. Eibach Prokits were 300/300, but Eibach ERS might be different front-to-rear. None of these numbers are verified.

Also, Ground Control recommends softer springs in the rear. I don't know why.

There is also conflicting opinions on the proper setup for drag racing. Some people say to stiffen up the rear to keep the car from unloading the front wheels. This might reduce wheel hop and the potential for broken driveline parts. Other people say to keep the rear softer than the front. This increases weight transfer to the rear during the launch and improves the overall traction.

So right now I don't know what I want.

[edit]: 600/600 is way too stiff *for me* on my 1G.