yes battery tray needs to be removed to have access to the spark plug near firewall.
I was not in a hurry and took my time replacing the spark plugs. took about 4 hours over a period of 3 days.

 

Good job. Thanks.

 

I didn't remove the tray, it is a tight fit though.

 

I've read that some people have to remove the tray and some don't. I'll see if I need to remove mine later this week. Thanks

 

Do not forget to remove the grommet first, it will give you necessary room.

 

Ok, got it. Im going to do mine tomorrow and see if I can do it like the Formula 1 Teams. Fast and perfect.

 

Better to replace spark plug boots and spark plug tube seals all together.
The old ones might still work since there are no oil in spark plug holes, but they are harder and less compliant compared to new ones. new ones may seal better.

 

On my '13, I needed to unbolt brake assy from wall to get to that plug as well as the battery tray.

 

yes I did the same.

 

What brand name plugs was you using, OEM?

 

OEM, bought from Lexus dealer online. for about $8 ea. why bother using other brand

 

The biggest risk with plugs is counterfeit. Buy from dealer or parts dealer with high volume/reputation like Rock Auto or national chain.