i think what david is saying is that if you only use a 2-channel amplifier, you only get 1 crossover frequency for all 4 speakers and they will be receiving the same signal.
if you went with a 4-channel or 6-channel you could crossover the 80's a little lower to get more mid-bass and possibly a little warmer sound overall.
the syn2 will work, but i think ideally the syn6 would be a better fit as it would give you
200W x 2 @ 4Ohms (ch 1-4 bridged to 80's)
155W x 2 @ 4Ohms (ch 5-6 bridged to 60's)
2003 X-2 MCX