is there a intake exhaust tune combo that works best?
what is the difference between intakes? is there one that is better than the rest and which i should aim for?
i have seen k&n, volant, and cold air inductions mentioned but not many others do all these perform the same?
Stock setup is already a "cold air intake". The flashy cone filters and metal pipes that everyone calls a "cold air intake" is most certainly NOT a CAI. NO "cold" air of any kind can be had by opening the filter element to the engine bay. They're for show and likely not as efficient at filtering out dirt so not only are you sucking in hot air (loss of power), you're sucking in dirty air which contaminates the oil and reduces engine life. "But they sure do look purty and sound kewl!"
About the only improvement that can be made is to smooth the flow of air from the filter box to the throttle body, so the Airaid MIT is ideal. You can spend big bucks on an aftermarket setup with a fully-enclosed filter box that ducts it's air from outside the engine bay. Or, you can keep the OEM setup that you already have that does that already. Still, any gains will likely be unnoticeable.
same thing with the exhaust setup
is there a header/exhaust combo that is good and won't break the bank?
i have seen $300 long tube headers and $1300 ones
Longtubes or stay stock. I highly recommend having headers coated since they radiate so much more heat into the engine bay than the stock cast iron manifolds. As far as the exhaust itself is concerned, the gases flowing from the exhaust port on the cylinder head, through a 2" primary tube, then though a 3" collector and into the 2.75" stock piping don't care what company made those pipes or even the metallurgy of the metal. So, aside from the minor brand design differences, a $300 set of headers will flow essentially the same as a $1,300 set. What you're paying for is the quality of stainless they are constructed of (metal thickness and rust resistance) and the quality of the design (fitment). If you don't live in a salted area, you should be fine with the cheaper headers. Yes, some alloys of stainless can and do rust. Just because something is made of "stainless" doesn't mean it won't rust.
Pretty much any free-flow muffler can help. There are countless options and you're gonna have to decide based on what you want and can research. Again, any gains just from the muffler will likely be unnoticeable.
could e85 be an option since mine is flex fuel
You can run it. Whether-or-not it's worth running depends on the cost per mile. E85 returns worse fuel economy, but it still may be the better value if it's cheap enough per gallon. Some report slightly more power when running it, though. You can get a tune to optimize running it, but then you'd always have to look for the stations that have it and this may not be so convenient in your area.
Speaking of fuel, these engines have consistently shown to run better on 89 octane or higher. I've noticed less or no detonation when running 89+ which surely should mean better performance since the PCM isn't retarding the timing to mitigate the detonation. If you insist on 87, just don't romp on it.
i have read about getting a cam or different gear ratios
i dont know anything about those really
Deleting AFM is advised nearly 100% of the time by nearly 100% of those concerned. You can disable AFM by having it turned off in a tune or with a plug-in module (Range device). But, actually removing the components is the only surefire way to avoid potentially catastrophic engine damage from an AFM lifter failing. One of the AFM components is the cam. So, when you're deleting the AFM system, it's a perfect time to install a performance cam.
Lower (numerically higher) gears can help with off-the-line performance which is where these engines lack grunt. But, it means the engine will be turning higher RPMs at any speed which, in most instances, means more fuel consumption.
is there other mostly diy mods i can do and get more power without sacrificing too much reliability?
Depends on what you consider "DIY". Take the aforementioned AFM delete for example. Swapping in a performance cam will get more power while INCREASING reliability. But, is a cam swap a DIY task for you?
Other than that, pretty much everything "DIY" are "bolt-ons": Intake, exhaust, tune, etc. and they won't sacrifice reliability if done properly.
are there things i should look into first before i think about more power?
Make sure all the basic maintenance/tune-up items are up-to-par: Fluids, filters, spark plugs, no leaking gaskets, belts, hoses, etc. Don't forget the transmission, transfer case, and differentials. Address any existing drivability/performance and maybe even emissions issues.
Check your engine mounts, particularly the driver's side one.
are there basic maintenance things i should look for to get more performance out of a high mileage engine?
See above. 130,*** miles is hardly "high mileage" on an LS-series engine. Although it IS in the "DANGER" territory for the AFM lifters. If yours ticks for a few seconds on startup after it's been sitting overnight, it's likely a worn lifter losing it's prime and even more likely that it's an AFM lifter. A small exhaust leak usually makes the same sound as a lifter and often subsides after a few seconds or minutes, so rule that out if you have ticking. The exhaust manifold bolts are notorious for breaking.
Check your tire pressures.
are there things i should outright avoid?
Hot air intakes, gimmicky spark plugs with multiple electrodes and/or made of unobtanium metals, throttle body spacer (unless it has nitrous and fuel nozzles in it
)...
any info or pointing me to info would be great
i would love to see before and after numbers on a lot of these mods but can't find anything really.
I've seen plenty of before and after dyno numbers on longtube headers to know they are a worthy investment. All the other bolt-ons are pretty much supporting mods. Cam gains vary wildly between grinds and tune gains vary wildly between tuning companies. Decide how far you wanna go with it based on your needs and proceed accordingly.
One thing's for sure, you don't have to spend thousands to get the most out of a naturally-aspirated Gen4. A few hundred on headers, a couple hundred on the MIT and muffler and a few hundred on a good tune (Black Bear
) to optimize everything and it'll be as good as it can be and even set up for the bigger mods (cam, boost, etc.) if you want more later.