I bought a used 06 spec v trans with only 27000 miles (car-parts.com) and swapped the sentra bellhousing with the maxima bellhousing. My friend switched the bellhousings, because both transmissions have the gear-sets mounted in the bellhousing, which requires some internal transmission skills to remove/install. I have pictures, but not sure how to insert them. Anyway, I should have the trans installed this weekend.
Total cost <600

; trans and bellhousing switch
advantages: LSD, extra synchro in 2nd gear