Another oil question

[Cobra1]

I have 8 qts of Mobil1 5W-30 "Fully Syn" I bought for one of my previous cars (since sold). I have an 2000 E320 that I bought new, only has 63k on the clock - wife drives, looks like new, always garaged. I looked at all my previous dealership invoices and they used Mobil1 0W-40. Any good reason why I shouldn't use this 5W-30 oil in my next DIY oil change on my MB? (I've decided to start doing maint. on it, dealer did all previous last 8 years.)