Do a lot of reading first. As you metioned, this has been asked on this site a billion times. As recently as a month ago. Read the past posts.
Read and understand the rule book for whatever group you plan on racing with. They are similar, but have slight differences.
Read my book. I may sound self serving here, but over 900 copies are in the hands of SM racers. The book must have some value.
Understand your budget. Do you have $30k to buy a front running car? Do you have $10k to buy a well used car? Do you have the $3k to fix up the used car? Do you have 300 hours to spend building the car in your garage? Do you want to race next week? Next month? or Next year?
Watch what you buy on ebay. Price is not always the best value. Example, a customer brought me a gasket set he bought on ebay. Box showed it would fit a Miata. Head gasket did, intake did not, valve cover did not and several needed parts where not in the kit. Example #2, I have sold cars on ebay. probably will again. A couple years ago there was a car advertised on ebay that said I built it. The car had my sticker on it. I brokered the car for a customer, but I did not build it, prep it, or work on it. Buyer be ware!
Good Luck and welcome to the family
Dave
Dave Wheeler
Advanced Autosports, the nations most complete Spec Miata shop
Author, Spec Miata Constructors Guide, version 1 and 2.0
Building Championship winning cars since 1995
4 time Central Division Spec Miata Champion car builder 2012-2013-2014-2017
Back to Back June Sprints Spec Miata 1-2 finishes 2016 and 2017
5 time June Sprints winner in Mazda's
6 Time Northern Conference Champion Car Builder
2014 SCCA Majors National point Champion car builder
2014 SCCA Runoffs winner, T4 (Bender)
2014 Central Division Champion, ITS (Wheeler)
2013 Thunderhill 25 hour winning crew chief
2007 June Sprints winner, (GT1, Mohrhauser)
Over 200 race wins and counting.
www.advanced-autosports.com
dave@advanced-autosports.com
608-313-1230