​The table below has a summary of which brand has the fastest cars for diecast, gravity racing.  This is organized by the number of distinct castings across my top speed tiers.  I'm not including the lower fast tiers (1-star and 2-star) in the counts, as I'm focused here on who makes the best of the best.

Some quick information to provide context:

• I race on a two-lane, 27 foot Magic Derby track (equivalent to about one-third of a mile).  The Derby track is 22% wider than a typical Hot Wheels orange track, allowing me to race more car sizes/scales.  
• I've applied graphite to the cars, which really brings out the speed potential for diecast.  I'll go into more detail on that in the future.  Some cars only improve slightly, but others improve significantly when dry lubes applied.  
• 5-star performers are the most elite.  4-star performers are the next, etc.  The higher the tier, the fewer the number of cars.
• See the home page for more details on track design, testing, etc.

A quick breakdown of the results.  Note that I have details for the 5-star cars in the Top 100 plus list, plus pages for the brands and series within those brands elsewhere on the site.  

• Diecast racing starts with Hot Wheels, of course.  60% of the highly ranked cars are from this brand.  That said, Hot Wheels has easily produced the most number of models.  So Hot Wheels is the big one, but using a baseball analogy, lots of hits, but certainly lots swings.
• Johnny Lightning is second.  As shared in the Johnny Lightning section, the fastest JL cars are from the first 13 years of their relaunch (1994-2007), which covers the Playing Mantis ownership years.  I should have the vast majority of the fast JL models, so this count may not change much.  But please share feedback if you have some input.
• Matchbox is third overall, but #2 for 5-star cars with 12.  The Matchbox brand over the last 10-12 years has produced very little elite speed, so not expecting many new entries, unless I can discover some older models.
• Kenner (U.S brand) has 26 cars in the top tiers and this is all the more impressive considering they are from one series (the Fast 111's).  That series was produced from 1980 through 1983 and consisted of just 38 models.
• ​Mattel of course owns the Hot Wheels brand (and Matchbox as well), but they have produced two key series outside of those brands: the Fast 'n Furious (1/55th scale) release from 2017ish and various Mattel/Pixar releases based on the Cars films.
• Siku (German brand) and Tomica (Japanese brand) have lots of new speed to discover.  I will be looking to expand my collection of cars in these brands and expect the totals to go up significantly over time.
• Ertl (U.S. brand) and Corgi (vintage UK brand) are likely limited for speed potential, but I'll keep looking. 
• I could use more information on fast Majorette (French brand) models.  
• Some other brands don't show up in this assessment, but do have 1-star or 2-star entries including ​Tiger Wheels, Metal Machines (by Zuru), Lionel (via the Revolvers cars), Maisto and Zee Toys.
• Road Champs produces mostly oversize trucks, vans, etc.  There are some very fast entries, but they are mostly in the Super Heavyweight class and are not counted here.  But I'll break those out in the Weight Class rankings. 
• No speed yet from Playart or Racing Champions despite several attempts.

Note that with only a few exceptions, there are not any redundant castings by brand in the rankings.  I only count the fastest version.  For example, the Probe Funny Car from Hot Wheels is counted once, the '69 Camaro from Johnny Lightning counted once, etc.

Rank	5-Stars	4-Stars	3-Stars	Total of Top Tiers
Hot Wheels	42	94	169	305
Johnny Lightning	7	25	40	72
Matchbox	12	16	19	47
Kenner	7	10	9	26
Mattel	6	9	11	26
Siku	2	5	6	13
Tomica		7	4	11
Corgi			2	2
Majorette		1	1	2
Ertl			1	1
Road Champs		1		1
TOTAL	76	168	262	506