Is it a good idea to quit job and stat mba prepration with experience above 5 years

NO, try to give 2-3 hours on weekdays and more on weekend from now to CAT or MBA exams and you can take break last 1 month to finalize your whole prepration. BEST WHISHES.

Better try for GMAT and go for Exectuive MBA since experience is above average

its a very bad idea, being out of the job will make us uneasy and put lot pressure on us.todards the end if u gain enough momentum and confidence, may be u can take a break.

NEVER. You might lose your confidence very easily. It's very hard to keep yourself focussed on CAT 24*7 too. Prepare well beforehand and if you do feel like quitting the job, quit before the last 3 months. Moreover for 5+ years of experience, you better try for GMAT or X-MBA like the other guy advised or even a MiM. A one year course in ISB or in the IIMs is better.

You can quit job only your family is well settled & your income is redundant. Moreover if nothing goes well I can take up my Dad's business. Because, once you quit the job, it's very difficult to regain it considering the prevailing situation. Think prudently & act accordingly. Or else, join coaching institute as a faculty & prepare. Few of my friends cracked it by working in a coaching institue after quitting full time job.