Hi Wil, the sports exhaust could well be making the bike run lean & hence the sluggish start, did you up-jet for it? if not you increase the jet size by 10% so if there's a size 100 in it, go up to 110.
Another possibility could be your ht coils are faulty, i've seen this happen especially on CBR's were owners have replaced carbs, ecu's, reg/recs & it turned out to be the coils.
steo, June 2009