Salaries in Malaysia will vary depending on the type of job and your qualifications and experience. Where are you currently living? In comparison to other major cities around, Kuala Lumpur has a relatively low cost of living. Have a read through our page on Cost of Living in Kuala Lumpur.
How old are your children? Have you considered schools in Kuala Lumpur?
Getting a work permit for Kuala Lumpur may be tedious. Read through our guide on work permits for Malaysia. The quality of life is difficult to pinpoint, as everyone has different standards and values, but according to the quality of life index, it is moderate.
Have a read though this article on the Pros and Cons of living in Kuala Lumpur. While there are many good points that can be made in favour of Kuala Lumpur, ultimately it's a matter of personal decision.
No, unfortunately you won't be able to work without a work permit in Malaysia. Though a tedious process, it's unfortunately necessary. Take a look at our guide to work permits: www.expatarrivals.com/malaysia/work-permits-for-malaysia
Best of luck.