With RTA runs becoming more common and having done both RTA and IL runs, I felt that there needs to be a guide on these differences.

IL Runs: IL Runs are the oldest and most common type of run in this game, and attacking an IL run be it with and without upgrades, and skip or full course follows pretty much the same strategy: Maximum Optimization. In an IL run, the goal is to get the fastest time possible with the fastest possible pod. In the fully upgraded IL category that is the oldest and largest record category, this has resulted in using only 4 pods now: Ben Quadinaros: Ben Quadinaros is the fastest pod in the game, and holds almost every single IL record now as a direct result.
Bullseye Navior: Bullseye Navoir is by far the most agile and reliable pod in the game, and holds the IL Records for Grabvine Gateway and Fire Mountain Rally that are most winding tracks. Both tracks are so winding that Bullseye Navior is actually faster than Ben Quadinaros on them. Bullseye also holds the Abyss Skip Lap Record, but Bullseye can only pull it off at 60 FPS and higher. Mars Guo: Mars Guo holds the Inferno Skip Records, and is extremely agile and reliable despite his chart topping width. He is also the fastest pod at the Abyss Skip Lap Record at 24 FPS. Wan Sandage: Wan Sandage holds the Abyss Skip 3 Lap record where he is by far the most energetic pod on the skip, though Mars Guo beats him in the Abyss Skip Lap Record at all framerates, and Bullseye at 60 FPS and higher. On the no upgrade IL category, Boles Roor is theoretically the fastest on every track, but he is so supremely difficult to control (Especially at 24 FPS that is standard on the N64 and Dreamcast) that he is brutal to use, and most would have far better luck and go faster using Ben Quadinaros and Mars Guo that are still extremely fast but much easier to use than Boles Roor.

RTA Runs: RTA runs are much newer, and require a much different approach compared to IL Runs. Whereas ILs are all about optimizing a single track, RTA runs are about running through multiple courses as fast as possible. The number of tracks in RTA runs ranges from 7 for a single circuit run of the Amateur, Semi-Pro, and Galactic Circuit, to 25 for all track and 100% runs. With 100% runs, you will not be able to use to most optimal pod for each track for the most part. In single circuit runs, you will be stuck with using pods playable from the start, and the pods you unlock from tracks 1 through 6 if they are unlockable. This leads to a greater focus not on what is the most optimal pod like in IL runs, but what pod is the most reliable. By reliable in RTA runs, it means being fast with the least amount of fatigue over a marathon RTA run session. A pod that is not fatiguing to use for long periods of time is exceptionally critical with 100% and All Track Runs without upgrades as both types of runs clock in at around 2 hours long. On the Galactic and Invitational Circuit tracks in Galactic Circuit and 100% Runs, you absolutely can not afford to crash often. One crash can easily have you lose the lead permanently, and especially on no upgrade runs. On Abyss, a crash isn't even needed to lose the lead permanently with and without upgrades. Simply falling off the top level one time dooms you by default in a full track run. Reliability also takes a drop at 24 FPS standard on the N64 and Dreamcast. The lower frame rate results in lower traction that renders low traction speed demons Aldar Beedo and Boles Roor unusable in no upgrade RTA runs on these systems. The RTA run reliability champions are the top 3 max upgraded pods in Ben Quadinaros, Bullseye Navoir, and Mars Guo. All 3 are the top 3 most reliable no upgrade pods for RTA runs too.