Originally Posted by grvv
The 3" is 119hz to 11000hz and the 4" 50hx to 10000hz
So that's good technical info...
the 119hz is probably "measureable output" down to that frequency. Without looking at a frequency response curve it is difficult to tell how much
output you will get from there.
That being said, 200hz is a workable crossover point from underseats to doors. Which might work with your 3" without pulling the soundstage down.
So unfortunately with the coupe, there are fewer options in the 4" range available but there are still quite a few. Have you already purchased the CDT?
Personally, I would try for a 8"/4" combo as its tried and true. So much info on this forum there is no need to reinvent the wheel, just tweak what others have done to your liking.