i was thinking about putting in a stage 3 cam in my el xr6, now the guy that ive been speaking to about putting it in said that if it is beyond the scope of the ecu i have 2 options, a new ecu, or a cheaper alternative of modyfing the map sensor. tricking it by modyfynig the frequency it runs at. is this a good or bad idea, i dont know too much about ecu's and im not sure if it will cause me any problems...

does anyone have any knowledge or experience with this?

I would retune the ecu. Playing with the MAP might help you fix a rolling idle but your probably going to mess the tune up elsewhere. If you chip the ecu with something like a chiptorque ($595) it will fix the idle and correct your AFR giving you more power and better drivability everywhere.

I see that you're in liverpool. Drop down to Crescent Motorsport (54 Macquarie Street) and speak to Joe. Let him know you're from Fordmods and he'll look after you. They do a range of cam and head packages and ECU's to suit.

IF youre on a budget re: ecu, a Megasquirt would be a great option. RPD is building 'plug n play' megasquirts that could be tuned on the Dyno @ Crescent.