I've got a 95 Impreza 5-speed gearbox with the 4:11’s behind my 3.3, had it in for over a year now with no problems.......But I'm pretty easy on it.
As for the RPM's, they won't be any higher with the 3.3 than they are with your 2.5, and the 3.3 has a higher redline......The SVX has a 9 grand tach.
The 4:11's would definitely give it some get up and go
, and make it pull a small trailer better, if you pull anything, that is.
Keep us informed on the swap, as it might help on somebody's project one day....
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Huck
Subaru Ambassador
92 SVX LS-Tour Magnaflow Exhaust, 5-Spd-AWD
88 XT6 AWD 5-Speed "Bride of FrankenWedge"
15 Impreza Premium Sedan
15 Crosstrek XV 5-Speed
My 5-Speed "How-To" Write-up
1976 Pontiac Firebird Formula
Current Count of Subaru's Owned.... "70"