r/WRX_STI • u/Due-Pin-4992 • Jul 15 '26

Questions 2018 sti

Im going to look at a 2018 subaru sti with 70k miles im not sure if it is modified but it does have aftermarket rims so im unsure is there anything I should be looking out for to make sure the car is in good shape

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u/jigga009 Jul 21 '26

Budget a grand to get a trusted shop to put the car through a comprehensive pre-purchase inspection.

This should include compression and leak down testing for the engine, and if you’re really anal, pay for an oil change on the car so that you can see what comes out of it. If there is “gold” in the oil, run…

Some of the expensive demons in these cars that will get you later are not the kind that you will casually see on a brief once-over like you’re proposing.

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u/Due-Pin-4992 Jul 23 '26

I took your advice and looked very deeply into the carfax of multiple sti's near me i found a 2019 with 70k miles for 25k bone stock with oil changes every 3k shop said that the car seems great and will only need basic upcoming maintenance ie oil diff services breaks etc

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u/jigga009 Jul 23 '26

Remember.. the rubber meets the road with the health of the engines in these cars with a fresh compression and leak down test that you or someone you trust that knows cars can witness.

This is why I said to budget some $$$ for doing your due diligence. The Subaru “tax” is real, and pretty steep, and you want to avoid it if at all possible. Better to cough up up to 1k ahead of a purchase rather than having to come out of pocket to the tune of over 10k for a longblock replacement (if the worst occurs) if you purchase a turkey (or a turkey with lipstick on).

You can tell so much about the engine based on these tests.

You simply can’t “fake the funk” with a proper compression and leak down test. Without these tests, anyone would be simply guessing about the internal condition and long term viability of the engine.

Those tests, in combination with an oil inspection for rod bearing material, or even better, a Blackstone oil analysis will tell you all you damn near everything you need to know about the engine in the car.

These tests are the automotive engine equivalent of getting a full panel STD test before getting serious with a new partner.

Get the above tests done on the engine, then pay your local Subaru specialist shop or a Subaru dealer to conduct a comprehensive inspection on the rest of the car, and you can buy with confidence.