wanting to start a new army 2000pts mech guard

Hey,
i've been wanting to start a new more competitive army, I play marines which win..... just not in tourneys. i have asked around my club and they said guard were a very tough competitve army, so here i am. I chose mech because i like mech, not sure how most things work though, only theory behind my choices


HQ:
Company command squad with 4 melta-guns,
Chimera with multi-laser heavy-flamer
= 165
Total = 165

Troops:
Veteran squad with 3 melta-guns,
Chimera with heavy-flamer multi-laser
= 155
Veteran squad with 3 melta-guns,
Chimera with heavy-flamer multi-laser
= 155
Veteran squad with 3 plasma-guns
Chimera with heavy-flamer multi-laser
= 170
Veteran squad with 3 plasma-guns
Chimera with heavy-flamer multi-laser
= 170
Platoon command squad with 4 flamers
= 50
Infantry squad with Commissar
= 85
Infantry squad with auto-cannon
= 60
Infantry squad with auto-cannon
= 60
Special weapons squad with 3 flamers
= 50
Total = 955

Fast Attack:
Vendetta gunship
= 130
Vendetta gunship
= 130
Total = 260

Heavy Support:
Demolisher
= 165
Demolisher
= 165
Manticore
= 160
Total = 490

Total = 1870

my idea was to have a 30man blobble on my objective shooting at tanks what-not, plasma-vets i thought could find a objective 3rd turn and just sit on it? melta-vets go rip some tanks a new one demolishers take on pretty much anything, manti-core pretty much the same the pcs and sws go in the vendettas and possibly fly to objectives last turn and pop down and flame some guys.

as you can see i have a 130 pts left im not sure what to get, i think i have enough anti-tank with 2 melta-vets, ccs, 2 auto-cannons, 2 'dettas 2 demolishers and manti-core which can all take out armour. I was thinking maybe a hellhound with hull multi-melta to get some infiltrators nervious? or a psyker battle squad with chimera, I would have to find points for these tho

so any thoughts on the list?

thanks for your time
Durian