How much do I have to spend?

Components, especially amps and speakers should be matched by how well they perform together and not by price tags.  Your Tannoys are 8 Ohm, 90 db speakers so they won't require a ton of power to drive them - just good clean power with high current.  If you tell us what Rotel power amp you have, you may find you have all you need right now.

Also, a lot of what you are seeking - depth, imaging, soundstage, etc. comes from the preamp and your Audio Illusions is a pretty good one but its starting to get long in the tooth.  I would make sure its still operating at factory spec.

The Rotel is giving you 200 wpc into 8 ohms, more than enough for the Tannoys.  You most likely have power to spare on tap that your never using.  I really don't think you need a different amp.

Again, an amps primary job is to drive a pair of speakers.  Everything else, soundstage, imagine, refinement, detail, etc. comes from the preamp and you have a pretty good one. 

So if you want to improve the overall quality of your sound, I would be looking at speaker placement  and your room acoustics first.

Hey, I am sure the Job 225 is a very good power amp.  I stand by my earlier statement though  - that an amps PRIMARY job to drive a pair of speakers.  It serves no other function.  So the amp should be properly matched to the speakers it is tasked with driving to at whatever sound level the listener is comfortable at with no fear of clipping or going into protection mode.

Your Rotel will do this @ 200 wpc and so will the Job @ 125 wpc.  THD are indistinguishable with both.  And there are literally dozens more that will do just as good a job.  Again, your speakers are very easy to drive.

But the true refinement comes from the pre-amp and I am sure the reviewers were all using one.

But if you want a Job 225 based on one user and some reviewers, go for it.  It does look like a very nice power amp for the money.  I was just trying to compliment you that you already have some pretty good equipment and maybe you don't need new gear.  Proper speaker placement and room acoustics play a huge part in the final result.  Good to you.