Replacing low beam bulb

[mnc-i]

The driver's side low beam headlight bulb went out on my 99 Boxster.

I am wondering do I go with H4, 55/60W Hella bulbs or go to the parts store and find H7, 55W bulbs?

My owner's manual (on page 156) states H7, 55W as the replacement bulb for the high beam and the low beam.

I searched Pelican parts and they are offering H4, 55W/60W Hella bulbs high beam & low beam (stock # 999-631-034-90-M44) for a 99 Boxster

I've done a search of headlight threads on the forum.

One last question, do you all recommend that I switch out both low beam bulbs (failed driver's side and also the passenger side)?

Thanks
MNC-I