Many questions

1) You can stick to PCM, or upgrade to 2.4. Both technologies work well, 2.4 is a bit more convenient.
2) If you are going 2.4, it would be better to go with Spektrum/JR or Futaba. The others do not seem to have enough customer base to make one feel comfortable. May be they work just as well, but a large user-base would help better product quality.
3) You can expect everything here to be 25% to 75% costlier when procured locally. Most people order over the internet. Personal items do not cause any problems in customs. Please check the other posts on this site on details of how to deal with customs and the Qatar Scientific Club.