Hi Guys, i am new to xbhp and this is my first post. So please bear with me if you find any faults. My brother owns a 2006 model thunderbird and i can vouch for the fact that the maintenance is quite high (every service is around 3K or more). The bike is just 4 years old but has undergone 2 rebores and is now in the garage for a third one. But i believe that is because he rides the TB like he rides my CBZ. If you buy a TB make sure that you ride like you would ride a RE and not try to rip on that. However i have not heard many complaints about the twinspark but the bikes are too new to comment.