Kenwood M845 will be around 13k
But since you're on a tight budget, I'd say get the JBL 60.4
Which would cost you around 8.5k
The JBL coupled with SONY GTX-1621s components which come for around 5k will give you a really good SQ !
It will be far better than powering just the rear coaxials
Later on you can run the rears with the amplifier as well since it's a 4 channel amp