Impressions on my TAC (1250)

Hello everyone.
I ask you some advice on my current TAC, and expecially about how to use better each unit (in your experience).

First of all, my meta: here we tend to play 1-2 times a month, and this TAC list is designed specifically for two house rules that we decided after some.....crazy cheesemongering.
1) 1000 OR 1250 pts (in this case, 1250)
2) No allies (so, this will be a "pure" dark eldar list).

Let's roll it off:
*Archon +3 Incubus + Klaivex on a Venom (Hei, we are on a boat!... liek everithing else )
*3 Troop (five men and one blaster) on 3 Venom
*6 Reavers (2 cluster caltrops)
*5 Blasterscourge
*6 Mandrakes
*2 Ravagers

Before this i was playing with 2 raiders and 10 splinterman each...but i've foud this not point effective (my opponents focus fire on turn one on my raiders and...they're gone).
The mandrakes are a somewhat experimental, but i've played them only once before and in that game they managed to nullify a 12 fire warrior scout that was holding an objective. In italy we say "squadra che vince non si cambia" ("Team who win you shall not change").

Good ideas?

What are you facing in your meta?

Principally,
GK, Tau, Necron and Eldar.
Sometimes (but not often) also that crazy spehsss merin that have FNP and some chaos space marine also.

The Archon with incubis is ok, I guess. But I tend to prefer a grot squad with an archite glaive succubus. Against GK, it can be troublesome, though.

Also, i've enjoyed a lot the "pragmatic guides": in particular, sorrounding an enemy veichle with reavers to prevent the emergency disembark. When i've managed to do that there was some rules discussion about it. Where the rules say that if a model cannot be placed (due impassable terrain or enemy units) it is destroyed?

I'd like to know that too!

We managed to consider the unit destroyed as the situation is very similar to a veichle ramming infantry without any escape route.

However, about this TAC i would love to listen at your opinions about wich role / where to deploy / what wait to trigger / what use for the units i've listed.

Under effect of damage on passengers: wrecked and explodes results fellas.
Its also a deduction process that arrives at that same conclusion.. Vehicle destroyed- can't remain embarked-> Can't normally disembark-> can't emergency disembark-> no models can be placed anywhere = unit destroyed.

I'd take heat lances (or Haywire if their army will be rolling out in shoeboxes) on the scourges rather than blasters, and reinvest that 20 points elsewhere. Perhaps a blaster and a haywire grenade on the archon, or a blast pistol/parasites kiss Gunslinger Archon.