Im putting in alot of work to my LS and i was curious what advice yall have on replacing the majority of the 20 year old vacuum lines?

Sizes and difficulty of the job mainly.

 

As you prob already know, you won't find the right size (diameter) hose at Autozone or any regular parts store. Toyota does sell vacuum hose in bulk fashion.
Remove a few hoses from the car and take them to a Toyota or Lexus dealer parts counter. They should be able to guide you to the right size. Instead of using ID or OD they are categorized using, No 1, No 2, No 3, etc. This is for bulk hose you can cut to desired lengths. Some hoses are pre-formed and sold individually.

https://parts.belllexusnorthscottsda...1420-1708.html

 

Recommended. Replace as much as possible, most are not difficult to access. Some of the molded to shape may be hard to find now.

 

I think this will help a lot of those that have a low idle when in gear as well.

 

Since some of the bulk vacuum hoses are routed in places that aren't readily accessible, it makes sense to use Toyota hose; it just seems to last a lot longer than the hose you get at the DIY stores.

Like others have mentioned, some of the other molded "air" hoses might not be available anymore.

 

The pricing at my local Lexus and Toyota dealers were a bit much, some were around $50! Instead i used that diagram to look at all the hose as most are right on top.
Seems that they only come in about 3 or 4 different inner diameters. With that im gonna gonna get some grease, new hoses, and possibly a vacuum gage for the interior.