Dave,

the fancy recievers you saw are probably of these 2 types:

1)Synthesised recievers - they allow you to go crystal less. The most common ones are the novak reciever made for the M8 and 3pk - both are high end radio systems. Futaba and JR also makes their own synthesised radios now which are not as feature rich nor expensive as the M8 and 3pk

2)HRS recievers - these come with the high end radios and just happen to be small and light - HRS is a high response system that makes the reaction time of the servo and tigger faster

So for the level you are at the moment, I would not bother with a high end reciever because you also need the fancy radio and servos to take full advantage - I dont think that you would notice the difference and if anything, fast radio gear might make your car feel twitchy because you would not be used to the reaction time. On the other hand, if you have the money and want to get something nice, get a good radio, reciever and servo - these things will last you for years - I am still using my 12 year old KO EX-II

Roger