Index:
(Level1-6) Top Speed upgrades: (Plug2/Plug3/Plug5/Plug8/Block5/Block6) Cooling upgrades: (Stack1/Stack3/Stack6/Rod/Dual/Turbo)

Be sure to check this thread out before you continue: https://www.speedrun.com/swe1r/guide/498gh

Notes: Cooling upgrades only have minor effect on your times compared to top speed so don't excessively reroll the junkyard for cooling upgrades.

Since you use Bullseye in the Semi-Pro Category compared to Ebe Endocott in the other Circuit categories a Block5 top speed upgrade will only max out your top speed to about 95% and while it is not neccessary to have a Block6 for good times it certainly helps out a bit.

While Amateur and Galactic Circuit basically only have one viable upgrade path, Semi-Pro has two.

1. Path Get Plug5 after Sunken City If the condition of the Plug 5 is >~60% when you buy it -->Start Dug Derby without visiting the Junkyard after finishing Howler's Gorge Get Block 5/6 after Dug Derby; Also buy any Cooling upgrade you find in combination with one pit droid.

Depending on the exact condition of your plug 5 you can run into money problems here if you happen to find a high level cooling upgrade and you might not be able to afford the pit droid (1000 Truguts). Should this happen you have 2 options:

1. Gamble, buy the cooling upgrade even though you can't afford the pit droid, which results in a 50% chance of your Top speed upgrade not being repaired (10-15 seconds time loss in Zugga Challenge). Buy the pit droid after Scrapper's Run!!

2. Don't buy the Cooling upgrade, either reroll the junkyard or buy cooling upgrade plus pit droid after Scrapper's Run

2. Path Get Plug 5 after Sunken City If Plug 5 condition is <~60% -->Pray to Watto --> Get Block 5/6 after Howler's. After Dug Derby get either of the best 3 cooling upgrades plus pit droid

Note: In rare cases (both Plug 5 and Block 5 were in really bad condition) you might be able to afford a Stack6/Rod cooling upgrade and pit droid on top of the Block5/6 after Howler's

The time differences of the 2 path's, assuming 1st try on every part depend on the exact part conditions. A rough estimate:

1. Path loses 10-15 seconds on Scrapper's Run due to block5/6 not being repaired yet
2. Path loses 6-10 seconds on Howler's Gorge due to low condition Plug 5

Best case scenario vs RNG impact From the above it should be obvious that the 2. Path is generally faster. However due to the part condition ranges being much smaller, especially if you want to avoid the 3rd junkyard visit, it is also more reset heavy.

That is the reason I made this guide.

From my experience the 60% threshold of the Plug5 part is a good guideline for balancing out best possible time for any given run and the chance of actually getting the parts you need without much rerolling. I have however not done any math on this so the 60% is purely anecdotal.

If you are doing the run with Skips you have the option to buy any acceleration upgrade from the junkyard or alternatively the level 3 acceleration upgrade from the shop after completing Baroo Coast. It's worth the small time loss if it makes you more comfortable with the Skip. Failing the Skip costs at least 35 seconds.