nj car title questions

[s3xrapt0r]

i baught my 300zx about a month ago and i had a problem with the title... basically the old owner signed it but never registered it and moved to kentucky, and left it for his family to sell. i got a new title ! but the way i had to do it was sell it to a used car delaership and buy it back for 500.00 including tax. so now the title is clean, im just wondering if there is a point of time when they void the whole title for nowt being registered with in a set amount of time. when you buy a car from a car lot it basically comes with some wierd sheet of paper thats dated with the day of purchase the dealers stamp, and the last line where you sign your name. its been 30 days and i havent got it registered.... the tranny is out of the car so its not moving anywhere and its not insured so i cant title it until its insured... didnt mean to ramble but i jsut wanted to give as much info as i could. the dmv wouldnt tell me anything other then you have 10 days and after that its 25.00... so im not sure if they ever void it after x amount of days