Yes, they announced the 500 will replace the 450.

Regarding pay, there seems to be some debate. ILC is paid salary plus bonuses, DRL (Praetor/Challenger PICs) are paid a daily rate plus bonuses. I havent seen the math but IF a DRL CA wants to work a lot of days (Say 16+ per month), they probably make more than ILC, some DRL CA want a minimum schedule (especially now that a lot of the RAC are upgrading) so they may only work 10-12 days per month and I am sure they make less than ILC.