hello hamza aziz,

the crash courses are the important for the best construction for the basic concepts.in my point of view there is no need for crash course ,if you're very strong in your basic concepts.because,they just gonna revise the concepts during short duration.it is my suggestion only,but you can go by your own decision.

the following are some of best crash course for  IIT JEE preparation,

• Kaysons education
• etoos education
• FIIT JEE

All the best!

I Hope this information will be useful to you.

if you need additional information,let us know to help you.

Thank you!!!:)