speed and power wise a 21.5 or 25.5 is probably the closest to a "normal" silvercan".
last night I ran a 21.5 for the first time in a sedan, it very much like when I used to run Tamiya GT3 silvercan.
for cost control, The Speedpassion stock spec system can't be beat, I just saw a motor/esc 17.5 combo for 89.00 on speedtechrc.com . I should know this, but I don't, If that system is available in a 21.5 that would be the ticket to a cost controlled entry level spec class. I do believe novak has a similar system.
that was the question right, entry level class.