Should I do away with 'is'?

Hello Guys,

I am new here. I would appreciate your help in assisting me to improve my english. Here is an excerpt of my short essay:

" Cesar Pelli (b.1926) [ , ] or [ is ] a widely acclaimed American architects known for designing  some of the tallest buildings in the world. He is also the architect of the world’s tallest twin towers [ – ] the Petronas Towers in Kuala Lumpur. Rising 452 metres, the Petronas Twin Tower is Malaysia’s most significant urban landmark. In 2004, the Petronas Twin Tower has been named as one of the seven winners of the Aga Khan award for architecture. "

Should I do away with the 'is' and replace it with comma? Is the hyphen sign appropriately used in this context?

Thank you. I look forward to your comment.

Regards,

EnglishNoGood 

Thank you for highlighting the error to me. Oh yes, does it make any difference if I use 'was' instead of 'has been' in this sentence:

In 2004, the Petronas Twin Tower [has been] named as one of the seven winners of the Aga Khan award for architecture. or

In 2004, the Petronas Twin Tower [was] named as one of the seven winners of the Aga Khan award for architecture.

Thank you.