I think you will find that Spark is not really suited to your needs. True. It does supply a good deal of code out of the box, but its all related to regular subscriptions. I would look at using Cashier and write the specific code you need instead of wasting time trying to modify a deeply opinionated framework like Spark. In fact, Spark is built on top of Cashier. Have a good look at Cashier. It is easy to use.

I'm not an expert in Spark, but I'll try to answer your questions to the best of my knowledge

1. No.
2. You can't combine features from separate plans to create a custom plan. Spark has no support for "Add-Ons." If I needed to add addons using Spark, I'd create two plans, basic plan and basic plan plus all of the addons. There's really no in-between with Spark (that looks nice).
3. In Team Mode, users need to create a team on signup, but if the team owner sends them an invitation, they don't need to create a team on signup.
4. I highly doubt they'll add other payment methods to Spark.
5. If you're talking about Forge/Envoyer, it should work very nicely. Haven't tried Spark with those two, though.

You would need to change your business model to utilize Spark, and even then it wouldn't fit all of your needs.

Thank you for your detailed replys.

Even Chashier only seems to talk about subscriptions. Im also concerned that it only seems to offer US payment providers (We are based in Germany and will have problems with handling customer Data in the us).

Can you suggest solutions outside the larvel ecosystem that would fit our needs? Im uneasy about implementing my own payment handleing system (even with the help from payment provider apis) and i would like to not reinvent the wheel (as no programmer wants).

@Lablicate

Take a look at the Cashier docs, https://laravel.com/docs/5.3/billing it says it supports Braintree, they support many countries. That sounds good for your situation but unfortunately there's also a warning that says:

"If you're only performing "one-off" charges and do not offer subscriptions. You should not use Cashier. You should use the Stripe and Braintree SDKs directly."

If you decide to sell some sort of a basic subscription you could then do one-off charges with Cashier. https://laravel.com/docs/5.3/billing#single-charges

But it sounds like they prefer you use an SDK.

We basicly sell high priced enterprise editions and plugins to companies and institutions (we are talking several thousand euro a pop). There might be an Software as a Service version on the horizon.

Given the information i gatherd from you guys we came to the conclution to let our finance department handle the payment and implement some (semi) manual way of unlocking users and teams.

Im still in favour of using laravel as framework (because i want to see how it compears to symphony and slim). I also might come back to spark if i ever need a subscription based system.

I hope the problem of selling virtual goods like steam and origin do will cause laravel (or somone else) to fill gap with some spark extention or new software product. It certenly would help folks like indie game devs and others.