timing chain renewal

[foggy08]

hello my 1.0 vvti yaris needs the timing chain replaced as it sounds like a rattle snakes tail. it has done 83k miles and has had a hard life . now my questions are .
1 is this a diy job . ive changed lots of timing belts before . never vvti . or chain.

2 do i need to change the cogs or just the chain, tensioner and guides?

3 how long should the job take and do you need any special tools

4 is there anything i should be aware of?

thanks for any advice