For RM18 psf on ploycarbonate is quite reasonable. Got some other contractor charge RM20-22 psf. Boleh lah bro but if u still cari  some more U can find RM16 psf. 

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Added on November 4, 2012, 1:06 pm

Yup bro, this type of louvers really can help block the sun & can give a good shading. But there are some disadvantage of using this :
1)  U cannot get a clear view outside & sky from inside of your house.
2)  If raining heavily, the raindrop can easily come in compare to using awning. Especially when it rains wt heavy wind.
3)  The airflow coming in & out from your hse will not be good compare to using awning.

Hope this info can help out...