- Atlas for a detailed look into the .ibt files
- iSpeed also uses these files to grab optimals and some other data that it uses - not familiar with loading them in manually, but it does have lap analysis so I am guessing that you can (?)
- if you are used to/like MoTeC, I believe Mu still works to convert those files so i2 can use them: http://members.iracing.com/jforum/posts/list/457406.page
ATLAS is probably the best since it´s officially supported and you can get loads of info from the iracing staff etc but i´m sure whatever you choose it will do the job for you
iSpeed is simple to install, understand and use. Tells me everything i need to know about the best way to improve my lap times. I have been pretty impressed with it so far.