I'm going to repost and paraphrase some info I put in my build thread over here. I'm installing my cluster this weekend after I get the parts necessary to reprogram the odometer. I'll take some pictures after it is installed.

Here's a Google Docs spreadsheet for the wiring necessary to use an 02-04 WRX cluster in a 98-99 Legacy. 95-97 Legacy will require a three wire speed sensor swap and wiring. An 05 cluster will work as well but you'll have to use a relay to invert the ABS light behavior. Keep in mind that sometime between 02 and 04 the WRX diagrams reversed the A and C connectors. Mine is made from the 02 WRX diagram where the A connector is leftmost when looking at the cluster from the back and C is rightmost. I haven't wired this cluster into my car yet but I am working on it soon, and as far as I know this diagram will be correct. If not, I'll update it.

With a minor change or two this diagram will also work for an 04 STI cluster with the red lighting and gauge sweep startup. I might try to score one of those someday.

https://docs.google.com/spreadsheets...it?usp=sharing

Here's a picture of one I built last week to put in my car with the side gaps covered.


Here's one (not mine) that exaggerates the gaps and shows the fitment. The flash makes it look worse.