Hi all, I have some question about the warranty things wanna ask you guys, I am sorry to ask these stupid question without doing enough research... but I've never owned a car that's still under warranty before so I hope you guys can help me out.

I just got my 05 sti off another owner and the car is still under 3/36 warranty.

My first question is, is the warranty still under cover if I bought the car used from an owner but not a dealer?

And... if the warranty is still under covered, will I able to go any one of the subaru dealer and I can still get the service? Or I have to go back to the one that the last owner bought the car?

The car has feel mods that I don't know will they void the warranty or not.
Mods are:

JDM pinks springs
Kart boy short shifter
Cobb brake pads

The last owner didn't know he has these mods and he think his car is stock (as he told me)... But I've notice these little mods is comes with the car. And I've checked the service record that he gave me. And seems like the last service he did is about 200 miles ago (replace the two rear struts). So if the JDM pinks is going to void the warranty, the subaru dealer will charge him $$$ for the replacement, but the record shows that the dealer replaced them for free.

Since I've notice some clanking noise from the rear and I think it might be the struts clanking. Could that be the struts didn't tighten well when the dealer replace them? Or should I ask them to check the rear diff. to see if there are any problem? Is it going to cover by the warranty? (The noise is coming from the rear and usually when I come to a full stop or rolling on the uneven road. Especially when I reverse the car. But is totally fine when I drive on the flat surface road. What do you guys think?

I am sorry to ask a lot of questions but I want to make sure the warranty things as I don't want to void it and lost everything
So... thank you very much guys!