What Railjack Reactor, Guns, Etc should I be buying?

[(PSN)Unstar]

I'm a bit stuck.  If I don't upgrade my Railjack with new guns, reactors, etc, then it will continue to be very difficult (and more to the point, excessively time-consuming) to complete missions with my Railjack.  But resources come at such a slow pace that I'm hesitant to build anything, lest I invest in the wrong gear and set myself back even further. 

At the core, this is two questions.  If I would like to be able to play Railjack in the Veil Proxima and kill 90 fighters at a rate that feels fun as opposed to a slog...

1. What ship parts (engine, guns, etc) should I be aiming to pick up, and in what order?
2. Should I not buy anything until the top versions?  Or should I buy some less than optimal pieces to make life less of a bummer until I can afford the better ones, even though that will may down progression since they all seem to require the same set of 3 or so highly-limited resources?

For context: I'm on PS4, have done all the missions in the Veil Proxima, and I play daily, generally for an hour or two.

To be clear, I am not really concerned with earning more Intrinsics, Dirac, or Avionics; those all seem to come at a natural pace for Warframe.  It's the materials required to upgrade the pieces of my ship that seem like they'll take forever and a day to accumulate and absolutely must not be wasted.  I need a plan!

Thanks in advance for your helpful advice!

 

Edited February 1, 2020 by (PS4)Unstar
I dumbed the title

[Captain_Rocket505]

It depends on what you want for your railjack. Now the weapons are both the easiest and hardest part. If it's damage you want, then farm zekti mk3 tech. Otherwise, get whatever weapons you want. Now, for the equipment

Shield: lavan has highest capacity but zekti has highest regen/ shortest delay. Vidar is a mix of both

Engines: vidar has highest base speed, lavan has highest boost, and zekti is a mix of them

Reactor(biggest part): vidar has the highest avionics capacity (90-100 at mk3) but lowest flux energy. Zekti has the higest flux energy but lowest avionics capacity, and lavan is in the middle 

 

Keep in mind all mk3 equipment has a unique perk that comes with it as well

[Fleuria]

For weapons, I would add:

Zetki provides good burst damage but overheats too quickly.

Vidar tends to have the best sustained damage.

However, the particle (slash) proc from lavan can give you even better sustained and burst damage IF your gunners know how to use it (they have to maintain fire long enough to get procs -- basically, if they can lock on and destroy a ship, and do so before the thing overheats, lavan particle procs *might* give you higher sustained dps than vidar.

But none of this matters if your machine crashes (which mine keeps doing 😞 )