I have a three way component set from Infinity. The midbass drivers are 6x9 and they don't fit in the doors. I'm using 6,5s from other brand in the front doors, the 4' drivers in the dash and the tweeters at the A pillar.
I'm using a 4 channel amp for the front stage (2 ch for the 4s and tweeters and the other 2 for the 6.5s) plus a bridged 2 channel for the sub.

The 4s and tweeters sounds well but they doesn't match the frecuency response from the 6,5s thru the stock xover.

I'm thinking on using an active xover, keeping the passive for the tweeters only and crossing the 4s with the 6.5s at a lower frecuency (lets say around 250hz) and using the 6.5s from 250 down to 80hz.

The stock passive crossover "sounds" as it is crossing a bit higher, closer to 500hz. This makes the dash mounted 4s sound a bit "empty".

The questions are:
1- How bad this could be on the 4s, powerwise, (playing 1/2 oct down)?

2- Could this ruin the SQ of the 4s as they will be loosing the Zobel network at the stock passives?