[BenLance]

Basically what do I need to take off of the 04 Impreza to get the trans to work in my 99 Impreza ?
Thanks

 

[Joe_TX]

Im looking to do this. What all did you have to remove and how easy was it all? if there is nothing wrong with my stock tranny, is it worth the swap?

 

[mike-tracy]

I believe the 2004 RS transmission has a different final drive ratio than your car. If so, you'll need to swap the rear differential as well. If you don't have a busted transmission, there's no point to the swap.

 

[SoCoNoHa]

Indeed, your transmission should have a 3.90 final drive, while RS' have a 4.111 final drive. You will need to also swap the rear differential, and I would keep the shifter linkage handy just in case. Is your '99 hydraulic clutch or cable clutch? I believe all the RS' were hydraulic. AND you may want to pick up a different Vehicle Speed Sensor otherwise your speedometer will be slightly off, but it's not necessary.

As for being worth it, I MASSIVELY prefer the 4.111 final drive transmissions. They feel much more sporty and I'm my experience the difference in economy is negligible.
I would say worth it.