I just bought an 07 classic with LBZ 3 months ago. And I'm going to tell you everything I wanted to know and didn't know that I should know.
1. All together...you have 4 filters. 2 tranny, 1 fuel, and 1 oil. From what I've researched, change the oil every 7 to 8K, the Fuel 6 to 7K and the outside spin-off tranny filter every time you change your oil...plus check your transfer case oil and if you can grease the joints. The internal tranny filter should only be changed during an overhaul or when you drop the pan..I heard around 50,000K.
2. Diesel fuel gels in extreme cold..so if you live where there is cold weather...2 things you can do...run a conditioner in your fuel...I run Stanadyne Performance Formula...or get a fuel/water seperator with heater...but some people run both.
3. Cold Air Intakes..(CAI)- the stock AC delco one is good. They say if you buy and aftermarket one...it just makes the whistle louder.
4. Exhausts...if you plan on buying an exhaust...MBRP or Silverline seems to be the most popular. And you have options.....Cat back and Turbo Back. A cat back system runs from the Cat back...and comes with a replacment pipe, muffler, and tip. A Turbo back system runs directly from the downpipe back. No muffler just one big pipe and a tip. If you do that..it will throw error codes. So you have to buy an EGR blocker plate..and a "fingers" stick to stop the codes. An EGR block plate stops the soot from getting back in the motor if you take your Cat off. And the difference between the two is the turbo back is suppost to give more HP and make it sound better.
5. Programmer- if you plan on getting a programmer.....stay away from Edge...from the research I've done...they have more problems than any other programmer. Banks is suppost to be way overpriced and not that great. And Diablo Sport Predator, PPE, and EFI live are suppost to be the best. Diablo is a good bang for your buck...PPE is just a good one period..and EFI live is for the big dogs (very complex). Also remember PPE HP is rated at the flywheel and not the rearwheels.
6. Guages. If you get a programmer...you should def. get an exhaust first...after that...you should get a Pyrometer. That monitors your EGT's...(exhaust gas temperatures). You don't want them to go over 1,300 or 1,400 for more than 10 seconds...if they do you will melt your heads. Especially if you are towing.
7. Tranny ratings. If you have the Allison 6 speed. Do not go over an extra 90 HP. They say if you do you will limp your tranny. But I heard you can limp it if you are Wide Open Throttle in higher gears. And by limping the tranny...I mean it slips gears and gets stuck and will throw error codes. You have to pull over and let it reset itself. Everytime you limp it you hurt it....and it gets easier to limp everytime. In that case if you are real serious about power..you can buy a tranny upgrade kit...but they are too pricey for me.
Well...other than that....I can't think of anything else. If I messed something up...please someone correct me..but I'm pretty sure I'm dead on about most of this stuff. If you have any other questions there are guys here ALOT more experienced than me. But in the meantime I hope this helps!!