[MINI-Fit]

Both the base Fit and Fit sport are in SCCA solo H-stock class.

You must use the same size wheels as what comes standard on the car.
Offset can be plus or minus 1/2" or as stated about + or - 6mm.
Hub bore 56mm. 4x100 bolt pattern.

Base Fit
14x5.5" +45mm offset
Tires
R compound (legal in stock class but not in Street Touring classes)
195/55-14 22.2" tire diameter vs 23" for stock
Kumho Ecsta V710 $115 each (closeout)
Kumho Victoracer V700 $125 each
The V710 is the tire of choice for best results but won't last that long, about one season of autocross with one driver. You can use them longer but they won't be as good/fast. Victoracers are good R compounds to start with and much more durable- may last two seasons or work with two drivers. Since the stock Fit doesn't have that much front negative camber you won't be using the full tread of the front tires, expect the outer edges to wear excessively. You can flip the tires so that the worn edges face the inside after about 30% of the outer edge is worn- this will extend the life of the tire and help to use the non worn inner edges. Flip only once is OK.
Tire rotation front to rear is fine with each event.

Fit Sport
15x6" rims +55mm offset
Estimated weight is 15 to 17.5 lbs each (based on some dealer sites that mention the weight).
Tires
For street tires treadrated 140 or more (can use them on the street and for autocross, no need to change tires at the event or can drive to event on race tires).
205-50-15 in Extreme Performance Summer tires-
Kumho Ecsta MX $81 each 220 treadwear 23.2" tire diameter
BF Goodrich g-Force T/A KD $136 each 200 treadwear
In 195/50-15 (Extreme Perf tires)
Bridgestone Potenza RE-01R $106 each 180 treadwear 22.7" tire diameter
(a popular street tire for autocross)

In 205/50-15 R compound tires (22.8" tire diameter)
Avon Tech R-A $119 each 40 treadwear (Auto-X or track)
BF Goodrich g-Force R1 $189 each 40 treadwear (good for track)
BF Goodrich g-Force T/A Drag Radial $115 each 0 treadwear (drag racing)
Hoosier A6 $197 each 40 treadwear (good for auto-X but expensive)
Hoosier R6 $197 each 40 treadwear (good for track, 2 driver auto-X)
Kumho Ecsta V710 $172 each 30 treadwear (auto-X or [track-wears fast])
Michelin Pilot Sport Cup $218 each 80 treadwear (better for track)
Yokohama Advan A048 $199 each 60 treadwear (better for track/wet track)
and Toyo Ra1 (better for track, more durable)
Fastest tires are likely Kumho V710 or Hoosier A6 for auto-X but do wear faster depending on how you drive.

Optional HFP 16x6.5" +55mm offset are not legal for stock classes but if you were in another class that allowed other wheel sizes then it is legal, but you can also run other wheels that might be lighter or even wider.