Topband: G3YXM Throbbatron Mosfet Amp

[Dan Zimmerman N3OX]

I'm looking to do some limited 160 DXing from my small lot, and my
maximum possible radial system is pretty tiny, so I'm looking to get
some power to make up for antenna inefficiency.

I came across this amplifier design:

http://www.picks.force9.co.uk/throb.htm

I wonder if anyone's built and is using one and can comment on its
performance.  I also wonder if anyone has any general tips and tricks
for building such an amplifier to get acceptable IMD performance and
so forth.  I do have access to enough test equipment that I can do
spectral testing on the whole rig+amplifier system after I've built
it, but what can I do to help insure that I'm going to put out a clean
Topband signal with this design or one suitably modified?  I'd like to
know what I'm getting into before I start.

The circuit looks very straightforward to me, especially because I
already have the parts for a more than 30V at about 30A  power supply,
so I *think* I can do the whole thing for $20 in FETs and maybe $50 in
parts that I haven't already got.  Mostly it's the cores for the
transformers and silver mica caps for the output bandpass filters that
I don't already have.

It seems a little too easy, and I'm worried that I'm oversimplifying a
bit... advice on things to look out for as I'm building and testing
would be appreciated.

Thanks and 73,
Dan