Ships & Modules

Dear OP: there are two general rules of a thumb that you should consider:

1. Do not fly what you can't afford to lose
2. You need about 1000 dps gank/tank to do level 4 missions.

Now obviously, some L4s are easier and some are harder. For instance, blitzing The Assault is easy, as you can just skip the first two rooms and do a single group in the last room. However, doing the last room in Angel Extravaganza can be insane for an unprepared character. So let's add a third rule to the above two:

3. start doing L4 missions when you get more profit out of them than out of doing L3s with whatever ship you're using for those.

Overall, forget about SNI and god knows what else people are throwing around. Nowadays, you can do missions in a badly tanked sniper in most cases. However, for them to be profitable, you want as much damage as you can get.

Now, I see you're in Amarr space, have Amarr BS 5 and missile skills T2, so I'll suggest something completely insane for you:

[Armageddon, pve]
5x Cruise Missile Launcher II, Mjolnir Fury Cruise Missile
2x E500 Prototype Energy Vampire

100mn Afterburner
2x Omnidirectional Tracking Link II
Phased Weapon Navigation Array Generation Extron

3x Drone Damage Amplifier II
Armor EM Hardener II
Armor Thermic Hardener II
Damage Control II or Armor EM Hardener II (I prefer DC because of the extra hull buffer, but Hardener is more effective for tanking)
Large Armor Repairer II

Large Processor Overclocking Unit I
2x Large Auxiliary Nano Pump I

Curator I x5
Garde I x5
Hammerhead II x5
Hobgoblin II x5

Stick those Vampires on a nearby enemy and you'll be cap stable as long as your AB is off. This fit should give you somewhere between 600 and 900 dps depending on your skill and more than enough tank to do all L4s. Now you can decide which way to go - if you want to keep training Amarr ships (great for Amarr space), you can train lasers and eventually switch to a laser boat or if you like missiles more, you can train Caldari Battleships and get a Raven / CNR instead. You can even train for drones, which will improve this ship and grab a Rattlesnake eventually.

Tldr: Just because something is cookie-cutter, it's not the only option. Look at your skills and you might be amazed at the options you have.

I can use large lasers and I have T2 small lasers. A nightmare is my dream ship but the cost...holy crap.

That sure is tempting. Looks like I could have the same tank as the raven but even more DPS with just T1 lasers. It wouldn't even require faction modules to beat out the Raven. On the other hand I only have a few hundred mil isk to my name so its hard to justify buying 2 PLEX just for a mission boat. How much isk/hr do you make with it?