IMHO you're fine with 3.73s if you just uncork the V10 and let it breathe, the stock exhaust is VERY restrictive and requires a few modifications starting with the Y-pipe which resembles more of a T then a Y. I redesigned mine using SLP 200cpi catalytic converters, eliminated the T and used a Merge Collector from Vibrant Performance, then i used a Flowmaster 50 Series SUV Muffler, next up was an SCT X4 programmer and 87 octane tune from 5 star.
The butt dyno feels like i swapped out the V10 for a V12 and it runs like a scalded dog.
You can swap out your gears and spend the same amount of money (probably more) and you won't be nearly as satisfied with the end result, you'll still have a dog for an engine and you might have some gear whine if they aren't installed correctly.
Other mods include a 170 degree thermostat, Wix 46418 air filter and D.U.I. SOS coils ($370), keep in mind my V10 is a 2008 model and it's also a Jasper reman.
The engine runs cooler, makes a LOT more power and if i keep my foot out of it, gets better mileage. My goal when building the engine was not to make more power, my goal was to reduce operating temps, increase BMEP, fuel mileage, volumetric efficiency and engine longevity, the side effect was more power.
There's always more then one way to skin a cat, this was my choice, do it like you want too..
This forum doesn't allow me to add pics in normal fashion but if you want pics send me a PM and i will give you my email..