is it cause it's tight? or just no room?

 

Both

Both rear plugs are difficult, but if you read a few of the guides on here and move the appropriate stuff out of the way, you'll be fine. I ended up moving my airbox out of the way, which nobody else seemed to require. This is definitely a fair-weather project and not something to do when you're in a time crunch.

Start with the front six and build up your confidence! Your sanity will appreciate nice weather and plenty of time.

 

Ahh garage day lol. Where are the guides??

 

https://5series.net/forums/e60-discu...27617/....Here is a thread I started when I was going to do my car, check out post number #3 this is what I used when I did mine, I didn't remove the air box either. Pretty easy though once I dug in. I have a 545 same procedure for 550. Good luck

 

The link was bad didn't go anywhere

 

https://5series.net/forums/e60-discu...please-127617/

 

I replaced mine last year @100k miles. Not hard, but as mentione cylinders 4 & 8 are right up against the firewall. Takes a bit of doing, but it can be done if patient. I used the same DIY Quarta2six posted. Good luck!