HOOKED on DRIVING Offers MINI Thunder IV Participants Discount. For those of you that are coming to MINI Thunder IV on Sunday Feb 17, 2013 at Thunderhill Raceway Park, Willows, CA and want to maximize your track time. Hooked on Driving is holding an HPDE event the day before, Saturday Feb 16, 2013 and is offering all MINI Thunder IV participants a special $40 discount package. To take advantage of this just got to: High Performance Driving Schools, Lessons, Driving Experience, HPDE, Professional Driving School click on events and scroll down to Feb 16, 2013 and click on the register button - then enter the PROMO CODE: MINITHUNDERIV