Look after the Irvine -take care with the running in phase- and you should have no issues with a long and useful engine life. As for the R/C gear-its probably best to go for new-depending on how old the unit is-but all you need is dual rates on your rudder...which is usually an option on all but the lowest specced gear. A 6EX -assuming it is 2.4-should be more than adequate for the type of flying you'd be doing with the Tomboy Sr. I'm not a Futaba user, so not familiar with the T6EX-but if the unit is 2.4 GHz (and not on one of the earlier R/C MHz bands) then you should have no trouble with it-though with a second hand unit you should probably get it checked over by a competent service agent. I'd ask around locally-there's a degree of merit in having similar gear-or the same-as the the majority of your local fliers-that way if there are any issues, someone else may know or have experienced them. If most of the locals use Spektrum, or FrSky, or Futaba, JR or whatever then it doesn't make a lot of sense-other than expressing your own individuality-in buying another brand just to be different....

ChrisM
'ffkiwi'