Most long time members here have read about members buying non OEM parts. In a few situations, it's OK, but for the most part, it's a gamble as China made parts in the last decade have a poor record of not working properly. Also, lots of counterfeit parts too. Spark plugs, O2 sensors and coils come to mind. Buy from a known vendor. Ebay has the most counterfeit with Amazon catching up fast. There are some success stories from long time members but they know what there're doing. If you're a gambler... or do you like to play it safe. When reading member advice, look at their post count and length of membership. Old timers can be wrong too of course.

 

I have purchased off Amazon, but always ensured it's a legit Lexus/Toyota dealer. It will show this in the "sold by" section.
Another option is https://www.mylparts.com. They are a dealer out of Roseville (?), CA and offer Club Lexus members a 10% discount. Under promo code use CL5

And for Desno, Rock Auto has worked out well for me

 

Yes, Amazon is almost as bad as ebay these days for fake/cheap parts masquerading as OE/OEM. Check the seller, as above ("Sold By"), to make sure its a legitimate concern.

 

Car has about 130k miles on it. I’m getting various parts from Lexus/ Toyota , carparts, or partsgeek. I’m only trying to get good quality products that last.

 

I don’t have any O2 codes. Only thing it needs is fuel pressure sensor but mechanic says it would be wise to change O2 sensors while we open intake manifold. Also I’m gonna have him change coils and spark plugs. I’m getting parts from Lexus/toyota dealers or online carparts or partsgeek.
car has about 130k miles on it and I bought it like 2 years ago. Planning on keeping it long term. Should I change these extra parts.?

 

If you and your mechanic are totally convinced that your fuel pressure sensor is the cause of your problems then the smart thing to do in my opinion is to do the valley plate reseal while you are in there and leave the other external repairs for a later date, you might see that it's either seeping or leaking when the manifold is off anyway and then you won't have to pay for any extra parts that may not be giving you problems right now and there isn't much if any overlap in labour so it's not going to save you any money to do them all at once.

With your mileage and age your guy is probably going to break some things on this repair that will require extra time. Also the info and conclusion on that other thread really doesn't make sense, The reason that 5v is used for reference is because using lower than battery voltage makes it more consistent, batt voltage varies a lot.
All a battery needs to do is drop to approx 11 volts and weird things will happen, before the reference voltage could ever drop to 5v the car would've stalled out.

Just do what you're comfortable with.

 

I am not a mechanic, but all the O2 sensors I have ever seen are located in the exhaust pipes. Not sure why he is advising you to change them when the sensor being replaced in under the intake manifold.

 

Plugs, Coils, and even O2 sensors on that car are pretty easy to access. Unlike the front-wheel drive transverse-engine ES models, for example.
If you have to remove the intake manifold to get at that failed part, I'd also think about swapping out the original starter.
Like doing a timing belt, though water pump is still good, since you're already there, and cost of part is low (around $160 for a rebuilt Denso starter) i'd do it.
Talk to your mechanic about it

 

Alright guys we’re back with an update. We finally got the job done. Ended up changing(actual problem) fuel pressure sensor($135 OEM), PCV valve($14) (which mechanic broke while removing), Intake Manifold gasket($25) (need 2 of em), Coils($180) and Spark plugs($60). Total labor cost $400. Did not change Oxygen sensors. Thank you for all the help. Car runs like new.