Andy,
First, welcome to the forum. Might want to introduce yourself when you get a chance.
The HD 1550 upgrade is a good way to get a decent boost over stock power. I'm guessing they want to put in the 211 or 203 cam and get you to about 9.5 compression ratio. Headwork makes ANY combo perform better and tends to give you smoother and cooler running as the stock heads are rather restrictive. You will leave anywhere from 8 - 12 HP and TQ on the table if you leave in the stockers and you not get the full benefit of the other mods that you do. Depending on how you ride is the key to your cam choice. If you want low end pull and decent increase in the mid to upper ranges then the 204 cam is the way to go IMHO. (The 203 is kinda lost in the HD lineup since the introduction of the 204, as the 204 has basically the same characteristics down low but opens up the top a bit more and stays harder longer). Lots of guys here are a fan of the 211 if you think you like to hang around in the mid to upper RPM ranges more often than not. There are some real good porters that will do your stock heads (one site sponsor here named BigBoyz has a price of $300 that does good work). Also Dewey Jelen is back in business and is one of the best in the business.
www.deweyscustoms.com
The dealer may try to sell you the SE line up of heads but IMHO the custom porters will get you the better numbers for the cheaper price in some cases. Get yourself into the 10 to 1 compression ratio if you are sticking to the 211, or 204 and you shouild get into the upper 80's to low 90's for HP and TQ should fall in the mid 90's or a bit higher. Nice boost over stock. If you are looking outside the SE lineup, the Andrews 26 is a nice runner with or without head work and the 37 with increased compression AND headwork is very popular. The 55 out of Andrews is also a nice performer with added valve lift. These are all good, RELIABLE builds that will have you smiling from the stock numbers. If you really want to get into the 100's there are Wood cams and higher lift offerings from the MOCO and other manufacturers, but then you are looking at other issues that may come into play. Hope this gets you started. Good luck.