With org and 2.5 and above it’s recommended. Many with 2 hasn’t seem to be any issues. 2.5 is at the border line and recommend, tho I haven’t come across it. 3 would be pushing it past it’s stress point.
Yea I really couldn't find many that went with a 2.5. The majority go for 2".
I went with 2" on my previous 4th gen and my other current vehicle. No problems what so ever after 3 years. I did see a you tube video of top hat spacers issues but after 5 years or so, which to me would be consider normal wear
Initially I was also going to go with the 2" top hat spacer but realized I only had a 1.5 rake and I would be nose high
So went with the Strut lift, first I did 1" and felt it wasn't enough and went to 1.5 to be completely level. Getting the upper control arm loose was hard.
I am some what concern with the angle so I might still end up getting new uca's