if you get a sakura sport get the new one to ensure parts support. in that price range i can also suggest the spec-r. iv'e done quite well with the car competing against some very expensive cars so far.
bumping up to $250 will get you into almost any 2011/2012 vintage professional touring car. tc6.1, s411,xray t3'12 and even tamiya. id go with one of those if your budget allows. saw a s411 listed for $175 i very nearly picked up.
id run what you have until the parts supply drys up. though you might be able to source other branded parts to fit certain things.. the belts are nothing special, bando sells custom belts you could make work.
really just depends how much money is comfortable for you to spend and how competitive you want to be. one usually influences the other lol... so be careful!
Sanwa M12 - Xray T4/16 - Xray Nt1/16 - CRC XTI-WC - ProAMPS - Hobbywing - ReVTECH - ORCA
www.irocc.ca - www.wcics.ca - www.vrcworld.com