I am very happy with my MHI 18k on a stock block. Stock like mannerisms with a lot more go. I've considered building the block and adding a larger turbo to get to ~500 wtq, give or take.

I'm curious of what kind of longevity can be expected under normal street driving conditions - i.e. some spirited driving, highway pulls, etc. - but not a dedicated track car. I know there are a ton of variables, but looking for a rough guideline. Are we talking 20k miles or 60k miles or even greater?

I assume a big part of this is maintenance. Outside of the normal maintenance done now, are full tear downs/inspections required at regular intervals?

I'm trying to get a feel for if I spend the $$$ on a built motor/turbo upgrade/supports - will I only get to enjoy it for three years before it wears out, during which I'll have to spend $ each year for tear downs?

Looking for feedback from someone with a built block on an X who has had it running for several years.

Thanks