There is no point.

The EJ255 and EJ257 are extremely similar.

If money is tight, you can't afford a trans swap. Selling your WRX and buying an STI is far more cost effective.

 

While similar the STi has dual AVCS which I always imagined made a substantial difference and @XJman confirmed that recently.

Overall the differences are substantial enough to just buy the STi.

 

it's not just the avcs but small differences between the two. They have different piston dishes and the STI also has a lower compression ratio.

As for the swap I looked into this once upon a time. The transmission swap alone can near 10k, the 6speeds in good shape are costly. It's not exactly a direct swap either as it comes with a host of things like the rear diff, axles, hubs, etc.

Usually it's cheaper to sell the WRX and buy the STI. I'm in the market specifically for an STI but it'll be a while. Car prices are absurd and I'm broke for the foreseeable future. I'd personally buy an STI over the WRX, but I'd not try to swap. I had a line on an STI swapped Forester a while back until I found out it was a half finished project. Noped out of that.

 

Ah. The old, WRX to STI "will it fit" thread. It's been a minute. Yes. In fact. It will. How many tens of thousands are you willing to spend to do it the right way?

I'm in the market specifically for an STI but it'll be a while. Car prices are absurd and I'm broke for the foreseeable future.

You're in luck. Legend has it, there's a white Recaro optioned 2018 STI with less than 30k miles, driven ridiculously easy, and only had a catback installed for a little over a year. (since removed for adulting) Otherwise, unmolested. You can purchase it at the grand KBB price of $2,000 less than what I paid for it. (Wing not included)

$2,000 off for gently used? There's no ridiculous pricing right now.

I'll send you my Venmo account when you're ready.

(really though, whoever ends up with my car next year is lucky AF, minus the automatic car was brush swirls)

 

Shoot for the price you're gonna pay for that swap I had a 2013 Sti for sale for 21k. It would be so silly to even attempt said swaps instead of buying a STI. Unless that car means the world to you and you wanna sink a boatload of money for not alot of return I suggest just enjoying what you have now.