AE Racer,
Hi. In my honest opinion , the SST '99 pro is still one of the best cars out there. I bought one when new and I used it for my backup car, because they are from England and sometimes I have to wait a while for parts. Arms and hub carriers seem to be the weakness on that car, so I bought aluminum hub carriers and have a couple of extra sets of arms in the pit box.
As far as performance goes, it is pretty dialed out of the box. The best investment I made was the 64-pitch gear adaptor. Just to give you an idea, I gave this car to my brother when he got tired of fixing his Legends Car and he was a force to be reckoned with right away. The majority of the competition uses TC-3 and X-rays, which are very good cars in their own right, but I am a firm believer in it isn't how new the technology is, it is the way a car is set up and maintained. Besides, it's cool to take something that is now three years old and go kick butt with it. I think that they are every bit as good as a TC-3, Yokomo, hpi RS4 pro, X-ray, Axis, or even the Mission in the hands of someone whom can tune and drive a car at it's absolute limits.
The car now sits idle as a backup for my axis pro, which is also an excellent car. My brother now races mod 1/12 as do I, but that all but dries up in the summer time.
Anyhoo, there's my $.02 and then some.