Reliability Mods/Things to Replace

Hi everyone,

I am looking to purchase a 2008 Mazdaspeed 3 soon. It has around 120,000 miles. The VVT and Timing was done at 90k along with power steering flushed, coolant flushed, thermostat replaced, and crankshaft oil seals replaced. It is stock. I can't stress enough that I want to keep it as stock as possible. I don't want to make more power, I just want it to be reliable. I tried to do as much research as I could on the subject before buying.

I am okay with small things such as HPFP internals, damond motorsport street mounts, etc. strictly for reliability and usual maintenance. I am aware the turbos and suspension typically need checked at this mileage.

I've heard people say walnut blasting should be done preventatively, and I've also heard people say it should only be done when you have startup issues (because it's an invasive process). Any advice on this? Any advice on anything else I can do to make the car feel fresh/new again from a maintenance perspective? I'm looking to try and not overspend but also make sure the car is completely healthy.

I've also seen the air oil separator stuff, but I don't really plan to add one unless people really think it is vital.

Thanks! - Callum