Complex Form Upgrade Cost, Expensive? Options

[fistandantilus4....]

For the first time I'm looking at playing a TM for a while, and specifically, at the cost for upgrading the Forms. Id rather avoid another discussion about TMs vs Hackers, I'm just trying to get an idea of how viable it is to continue to upgrade/

The cost for Forms is like upgrading spells in previous editions to a higher force. It seems prohibitvely expensive, like you'regoing to have to hedge your bets against raising your form rating if you're near your max, in case your get to raise your Resonance some time soon, otherwise you risk wasting karma.

My questions mostly for anyone whose played a TM for a while, and dealt with this. Does Threading cover the difference? Does jacking up those Forms make them over powered in the long run? It seems that with a lot of perp time, you could prep some Sprites to maintain a Thread, Thread up your Form to a decent rating, and go, but that seems to take a lot of extra work to get a decent Rating.