How can you say that? A lot of guys here driving Pro4s run with mod and never broke their diffs. The Pro4's bevel gears easily wear out that's why they came up with the 1.1 version. The 1.1 bevel gears have plates on the edges that makes it more durable compared to the old ones.
Many people have the wrong impression on the Pro4. But the car speaks for itself. Some guys here even said that the Pro4 is not a good car out of the box. Not true! Hara proved it and so as the other champions who drove their Pro4s to victory.
The Pro4 is a very competitive and durable touring car. Tons of hop-ups from HPI and from the aftermarket brands like, BMI, Square, Jet Racing, Speedmind, and a lot more. Before I got mine, I did a few research on which car is better. My choices were:Tamiya TB EVO 4, HPI Pro4, AE FT-TC4 and Yokomo MR4-TC SD. I chose the Pro4 because of parts, competitiveness, durability and most important, performance.
I don't drive as good as the others, yet. But I will get there because it's only been a few months since I got back to RC racing. The last time was 1996. I bet that most RC owners and drivers with new cars in this site wouldn't win against my Pro4 if I let Hara, Surikarn or Andy Moore drive it.
Lastly, just because a lot of newer cars have been out doesn't mean that the Pro4 is outdated. Definitely not. It is still race worthy against the newer counterparts.