DNA Stage 1, Stage 2 and Stage 3 for XT660Z
 

DNA Stage 1 filter and Stage 2 airbox top cover to suit XTZ...

http://www.ebay.co.uk/itm/Yamaha-Xt6...item27fde5bb99

...and a Stage 3 too!

http://www.ebay.co.uk/itm/Dna-Filter...item27fdd26633

What are these items new ?

This is where I'm getting very confused, you've linked the first one as stage 1 and stage 2 but the seller has stated that the other filter is a stage two

The seller hasn't quite got the description right. Go by my links.

These items new (from BR Special Tuning) are:

Stage 1 main filter = �33.19
Stage 2 airbox top = �30.94
Stage 3 airbox side cover = �70.44

The ebay items are potentially a very good deal... for someone.