What are my options for doing a 6MT swap?
-There are really only 2 routes:

1) This parts list includes:
• Transmission
• 6MT clutch fork
• Auto driveshaft or STi driveshaft and enlarge the holes on the driveshaft and yoke or switch the yoke on the R160 to the bigger R180 yoke if you can get one.
• Put 3.90 gears in your R160 Differential (if using an 06-07 transmission with an 02-05 R160 there is no need to change anything with the differential)
• Reuse your WRX axles
• STi shifter linkage
• 6MT transmission mount (5MT and 6MT mounts are different)
• DCCD controller (optional, but recommended)

2) Here’s the expensive but stronger way:
• Transmission
• 6MT clutch fork
• STi driveshaft
• R180 differential
• STi axles
• STi hubs
• STi knuckles
• STi Brembos (calipers, rotors, pads) technically you only need the rear
• STi strut assembly (05+ knuckles)
• STi shifter linkage
• 6MT transmission mount
• DCCD controller