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Message: [QUOTE="freddie, post: 1546758, member: 216"] Thought I'd follow up with an update. SDK Tunes (have not asked for any revisions YET) I still have 3.55 gears with 35s. I have checked for boost leaks and feel confident that there are none - there were some originally but I have found and fixed them. Even checked with soapy water and I can't find any bubbles. I did find that my driver's manifold/up-pipe connection leaked, it had soot showing a leak, so I snugged that up. Truck is a blast to drive IF the turbo is lit. It seems really easy to get under the turbo though, and even unloaded in overdrive at 50-55mph, ~1400 RPMS, it just doesn't seem to hold any boost unless you are manipulating the throttle to build some. Pulling a 5k trailer through some rolling 55-60mph hills, I had to shift out of OD to keep from smoking, just because the turbo would not stay lit. It was right on the edge of lighting the turbo or getting smoky, and I end up driving watching the passenger mirror for smoke. I want/expected a lot better driveability than that. If you roll into it to get the turbo lit or downshift, it does spool extremely quickly to build boost. At this point I really want to regear. I was set on 4.10s, but I am also contemplating a change in tire size. Wife and I want to buy a truck camper and tow decent size fiberglass boat - for stability sake I think it is best to drop down a few tire sizes and run a tire with higher rating too. Anyways, if I stay with 35" tires, I think 4.10s would be perfect. But if I drop to a 33", not sure whether to go with 3.73 or 4.10 gears, and I'm curious what everyone's thoughts are. I already have the 4.10 gear sets for the change, but would need to buy 3.73 gearsets if going that route. I am leaning towards 4.10 gears unless someone is going to talk me out of it. I added an attachment that shows some RPM calculations based on different gear ratios and tire sizes. [/QUOTE]