Hello

It totally depends on you  whether you want to join classes for IPMAT or you can crack it by yourself.

There are two conditions-

1.You can study by yourself,buy books that helps you to crack IPMAT and half of the things in IPMAT is from the syllabus that we studied in our schools.If your concept is clear you can do it by yourself.

2.Second condition is that if you join coaching classes,that will help you to guide to how to crack IPM and also they will make you well prepared by giving Mocks(That is the plus point to join coaching).Also they will make you well prepared for the GD/PI.

I would suggest you to join coaching classes for better result.

I Hope This Helps

Good Luck!