On my 1989 car it was four hex head 13mm.
The FLXM13 made it possible for me, although a good range of long, stubby ratchets and extension handles helped a great deal.
Just in case I was faced with allen bolts, I got some 1/4" drive allen keys and swivel end extension bars.
You can never have enough tools, but after 20 years of collecting it is finally getting easier
Good Luck, pace yourself and it is not too difficult a job.
Richard