There is bound to be some debate on it, but IMO, the stock ZS carbs are superior to the webber carbs for normal street driving. Converting over to fixed venturi webber carbs will probably increase your fuel milage and top end power slightly on a stock engine, but you will loose some low end torque.
If your really having problems with keeping your carbs in tune, it may be time for a major overhaul on them, new shafts, needles, main jets, shaft bushings, return springs, etc., not just a kit.
Be sure there are no other issues going on with the engine that may be acting like a carburetor problem also.
Properly set up ZS carbs in good condition are really not nearly as unreliable as thier reputation, besides, ALL of the downdraft webber conversions for the TR7 just look ugly under the hood. /ubbthreads/images/graemlins/wink.gif