If you think your car is a lemon, don't go with a jack of all trades attorney, hire a specialist like Jon Buxton specially if you have a Lexus or Toyota. Unfortunately our Lexus TX did turn out to be a lemon (first year production TX350 with lots of issues) and Jon was able to negotiate for us a very fair offer.
All in all, it did take about three months so some patience is required, but trust in the process and trust in Jon. Easy communication (same day email replies and returns calls).
For the initial review, you will need all the work order / invoices (ask the dealer to print them all out) + your initial sales contract (that super long piece of paper you signed when you bought the car that lists all the financial numbers). Good luck!