Help, I am taking my Grade 8 Piano Examination this Year and I really need help on how to recognize chords by ear at one glance for my Aural Component.

I am having difficulty recognizing chords especially in the second and third inversion, its progression and singing the lowest part after it being played twice by the examiner.

As for Modulations, I can recognize modulations to relative major and relative minor, but some others , like modulation to subdominant major/ minor and supertonic major/ minor really makes me so nervous.

As for singing the lowest part, I have tried playing only the lowest part on the piano, but when all the other voices are played together, its sound is often blurred by the other colours of the voices and hence the trouble again. Plus , how do you focus on training your memory to recognize that phrase and sing it out, especially if you need to distinct it from other voices.

How do I improve my overall ability in this area. Are there any pieces by any composers or useful resources that can help me to improve me chord recognition.
I m really nervous about my coming piano examinations .
Help much appreciated!
Thanks!

this sounds like theory exam than piano exam. Not sure which school you are from, but you may want to remind them that piano exam is playing one or more pieces and be judged on that playing.
As far as your question,I am not sure about a specific method.However I would advise you to do recognition exercises. What I mean is the following:

Get a friend to play individual notes or chords for you.
and you will have to recognize the exact notes within5 seconds of them being played. While doing that you can also work on recognizing the quality(major, minor etc...)

I hope the above helps