Does impedance of a speaker change when one bi-amps?

WOW, you guys complicated that conversation.

My Integrated amp rated at 250/8-425/4 shut down driving my power hungry speakers that have 2 pair of binding posts on back they’re 4 way 6 ohm rated and manufacturer recommends 500 watts. My question for the experts assuming I can get the amps output levels matched is, Would my integrated be less likely to overheat at the same spl if I added a 2nd amp, removing the strap to horizontally bi amp the speakers? also if I got output levels matched would amps of identical power be necessary or could I wire a pair of 350 mono's to the bass of each speaker and use the int to drive the top end?

Thanks for the interest. My Int is A Hegel H360 and the speakers are Revel salon2's. Though I chose the unit to go with the salon1's I had at the time i'm happy with the synergy with the new speakers and now i've had the Hegel just over a year and the new speakers since march I did manage to trip the thermal protection once. I know heat kills and I horizontally bi-amped my R105/3's successfully in the past. The 2nd amp made a big difference with the kef r105/3 speakers really filling out the bottom end. 

The h360 has been in my system over a year now and only shut down the one time. I owned a pair of kef R105/3's for over 20 years and they had 93.5 db eff so compared to the salon2 at 86 db they played considerably louder with less power. I read the review and every other I could find after hearing the h360 at home and being so impressed with it, I had never heard of the company and needed to know more. When it shut down it was only warm to the touch and I really probably shouldn't be chasing the ear bleeding levels those old kef's could reach anyhow. When the music is coming out so clean it's easy to get in trouble with the volume control.