So, my new game is finally at some kind of playable stage and I need some help!

My game is a set collection card game.
First I want to note that this is supposed to be a short (30 min), fun game for me to take when I travel.

It involves players gathering components to construct vehicles (victory points) and interacting with a bidding system and action cards which they can use to enhance themselfs or hinder opponents.

Each turn the player can do the following:
Purchase a component card for 2 gold.
Purchase an action card for 4 gold.
Sell a component card for 1 gold.
Sell an action card for 2 gold.
Use the correct components to construct a vechicle.
Trade with other players.
Play an action card.
Simply pass.

Players start with 2 gold and generate a further 2 each turn.
Action cards do various things from reducing the cost of cards, generating more gold per turn, hindering your opponents and ending turns etc.

When a player draws a card from a deck, they need not pay for it immediately, they may instead place it in the open area for the other players to bid for should they choose. Only if the player chooses to take the card do they have to pay for it, regardless of choice they end their turn.

The victory condition is to construct one of each vechicle type (5 in total). Each vechicle needs at least four components to be constructed of varying types.

I hope that all makes sense.

Here are some issues that I have so far, messing around with my VASSAL prototype:

Play is kinda slow - especially at the start it feels like you're just either passing to get coins for actions, or grinding the components deck.

Victory conditions - I'm really not sure if it would be best to make this one of each vechicle, a certain number of vechicles or a random fixed amount of each decided at the start of the game.

Action cards balancing - This is a tricky one, some cards seem like a really cool idea (such as end the round for all players) but compared to others they are a little underpowered (against say a generate +1 coin at start of turn). I've tried to address this in three ways:
1. Being able to sell action cards back - If you get a card you dont want or isn't too powerful you can at least get half your gold back.
2. The player can only possess 1 or 2 of some action cards, others are one use only.
And by adjusting the number of cards in the deck depending on how useful they are (8 miss turns to 4 more golds etc.) The biggest issue with this is it makes the actions deck quite large due to the needing to have at least one of the powerful cards for each player. Otherwise if there is only 1 or 2 the players who possess them will win far too easily.

Auctioning - This is kind of tacked on at the moment, but I like that it gives players getting back luck on the component draws a chance to catch up and not fall behind. Any thoughts?

Component 'alignment' - I'm toying with the idea of each player having a component alignment at the start of the game, this will enable them to have advantages when dealing with this component type such as; no cost if drawn from component deck. One less required from the vechicle build requirements. Can sell for 2g instead of one.

Let me know what you think, I've got the cards all created and loaded up into VASSAL and it's quite playable, I just need to iron out these bugs.

Cheers,

Glenn