My jeep came with the factory Jensen 6 speakers, I have replaced the 2 door speakers with 6.5s and the hatch speakers with 6x9s. I'm thinking about adding another set of 6.5s up in the dash where the factory tweeters used to be. My question is, would having this other set of speakers running of the factory tweeter wiring put too much stress on my headunit, or would it be okay?

 

I have 400 watt 6.5 subs in my doors, additional tweeters in my change slot in the console under the ashtray, 1200 watt 4 channel amp under my steering column and two crossovers preamp, 250 watt 6.5 3 way in the hatch, 350 watt 4 way in the crossover bar I got out of a 97 xj and a 1200 watt combo 10" sub strapped behind the rear seat hooked to the center seatbelt with ratchet straps. Clarity! I can take pics.

 

Wow......... I gotta see this......pics please.......

 

the concern is the resistance of the speakers. I have no idea how low your head unit is stable to, but if you wire two 4 ohm speakers in parallel, you've dropped it down to 2 ohms which is basically trying to double the power draw from your head. or if you wire them in series you've bumped it up to 8 ohms and cut the power from your head in half. I'd say look into a good 4 channel amp.