I agree.

At $3500 budget
Those 03 heads will benefit from a good street port job with springs to accommodate the valve lift you'll want. Have compression releases added. At 95 inch bore, different piston options to get the compression you'll need. cams, exhaust. If set on true duals, a set of Rineharts maybe. True duals look cool on an early TC Road King
The rabbit hole is deep

 

You are right and I agree; I did not look at the kit specs. We do agree that the OPs cam and exhaust choice should change and that more homework is necessary to avoid ending up with a turd.

I would not stop at 95" but bore to 98"; lots of piston choices for target compression. Three cubic inches is not much but it's free.

 

It would be smart to consult with an independent harley shop who can also handle the tuning. It might actually cost less in the end, considering you’re new to HD’s. DC cycle in redbay AL seems to have a lot of happy customers. There’s also DC v-twin in Georgia who has a good rep from what I can see.

 

I am not sure I would compression releases. Depends on compression, I would research that. Also depends how much would it cost, since heads are of anyways.

I went 88 to 98 to 95. I probably lost some going back to 95, not sure I can tell

95 is tried and true, cheaper boring existing. Or get take offs and bore while riding.

95 can be bored over. I would want the ability to do so. My 98 nickelsil couldn't be. Not sure if 100 cast iron S&S can be

 

If you don't have enough compression to need compression releases you don't have enough compression...period.

 

It might also make more sense to look into selling your slick 03 anniversary bike and upgrade to a later twin cam model. ‘12-‘16 came factory with 103’s, brembo brakes, better chassis. 14-16 have a better front fork and a little more power. Your bike won’t be worth any more to most buyers after you dump 3500 into it, and want to upgrade later.

 

Yup
Manual compression releases are cheap enough. And they'll be there when you need them