dont use wd40 its really not a good idea, the reasons are as follows:-

1. it contains silicone, get it anywhere on your cr and if you ever need anything painting it will make the job a right ache!

2. it doesnt lubricate very well

3. it tends to make dirt stick to it, but it doesnt have enough 'body' to alllow the dirt to move

4. it has a reputation for causeing damage to plastics/wirring looms

do door hinges etc with spray grease (much better) lithium is good, but leave white marks, my favourite is the type for motorcycle chains...sprays on nice and easy then 'sets' designed not the be thrown of chains and to be wash resistant so you KNOW its goign to stay on your hinges!

dont forget to do bonnet hinges and latch mechanism!

seen a early 90's 740 nicely rusted out (boot floor, rear inner wings, rear valance, 3 days work in the shop welding it back together!...sure the rust proofing was good WHEN they left he factory but it may WELL have been damaged by now - thats why you re-seal! and you may as well do the internal structures in case they missed a bit and to account for condensation (the biggest casue of terminal rust in cars)