"Yes", Such a device will affect the sound of the system. There is simply no way around that. And the better the system? The more detrimental those effects shall be.
I looked into this awhile back for a friend who couldn't see any other "real" option at that time. But I do advise against it.
Having said that. If you absolutely "Have To" do this...
Two thoughts for you. First, Unless you (Need) processing "like an active DSP for use as a crossover with BSC"?? Then the device used "Must" be passive. (If you have to plug it in, add batteries or charge it for use? Just Say No!)!
[If you need the processing? That is another discussion entirely}!
And secondly, I still believe that either a, "ETO" device or SCC/SP or LR system from "Mapletree Audio" is the ONLY way to go. Unless you "yourself" can DIY a device of this nature from scratch. "Which really isn't that hard to do". But knowing the design elements needed and then the prioritization of those elements is beyond many people. And of course, there is always the matter of "Your time" to consider as well.
I believe that "Mapletree Audio's" devices for this still begin at about, ($1,000). Which is a bargain considering the parts used and the quality of the people who will design/build that device.
If you are seriously thinking of this as an option? Contact Mapletree Audio and tell them about your specific needs/wants in this project and ask for their thoughts as well. You will quickly discover and also understand why I called these devices, "A Bargain" at their given price-point. "Simply by chance, I had noticed an article mentioning "ETO" from Mapletree in some audio related mag I was perusing, while my friend was again actively in my ear seeking my advice on the subject. I decided to contact them by phone to get a feel for the company. And I was seriously impressed by the time that first conversation ended".
Well, Thats my two cents...
Good Luck!