Cam and Crank seals on 105k?

[WRXtranceformed]

Well, I've got almost 93k on my TL and it's about time to start thinking about doing the timing belt service (usually around 105k)

There's a guy who does timing belt kits for real cheap on Acurazine. Here's what comes in the kit for $295:
Timing belt, water pump, bearing tensioner, hydrolic tensioner, and all drive belts

I asked him what optional parts people are ordering through him for this service and this is what came up:
Spark plugs: $14 each
spark plug seals: $2 each
valve cover gasket: $5.75 each
timing belt idler: $35
cam seal: $4.95 each
crank seal: $5.50

I'm definitely doing the spark plugs, don't think I need the seals. I will likely get the valves adjusted so the gasket is going to be needed, but what about the timing belt idler, cam seal and crank seals? Apparently some folks replace the thermostat too. Any thoughts on the TB idler, seals and Tstat? Necessary or no? I think the thermostat is like $25 shipped.