I guess what I'm asking is how does the BJ4 compare to the XXX4 as far as handling? The XXX4 I think I had set up with a spool and one way bearings on the front and it had A LOT of turn in. No amount of chassis tuning could get the car where I really wanted it. Don't get me wrong, it was fast through the turns but you really had to take a perfect line through each turn, it was very unforgiving. I always wanted to try a ball diff in the front of that car but with the inability to practice it never happened. At any rate, the track I'm going to race at now is essentially set up for 1/8 and 1/10 scale so it's large with sweeping turns so it ought to be more 4wd friendly. I've been to plenty of tracks and seen guys with "outdated" chassis' kick plenty of butt. It really comes down to driver and set up at the club level. But you're right, a lot has changed since I raced last as far as electronics. I assume I can have my Turbo 35 reprogrammed for LiPo? and maybe reuse my servos but that's about it...