Where do you draw the line? Until you're spending £100k this remains relevant. At any budget there are better examples of ordinary models available.
For only a 'little more' than the nice but ordinary A4 I posted above, you can get an even newer, nicer ordinary A4, etc.
I completely agree with you that a V6 is nicer than a 4 cylinder. To the point that I won't buy a 4 cylinder myself. But I also don't view a V6 Audi after looking at a 1.6 litre diesel Nissan, so it's clear that what I look for and enjoy in a car is different to him.
He just wants 'some nice car' and I think that a newer ordinary car will 99% of the time be nicer than an older car that happens to be much faster but more dated inside and out.
I draw the line by finding balance. Not 15k on a 1.4 B9 A4. The interior is average in quality. If you're spending 15k on an A4, you could spend 25k on a 340i which will be an infinitely more exciting car.
I'm also not suggesting an RS6, which I doubt Lee would appreciate significantly more than an S4, for example.
It's about finding the balance.
I understand he wants a just a nice car. I'm saying that you can wait another month or two and not have "a nice car", but a really nice car. I'm giving him options, options he may not even know he has, or really understand why he would/should consider them.
I know a few people like Lee, who have lived within their means for many years, and then come into money. It becomes the norm for them. Now, though, it doesn't have to be. You can strike a balance.
I'll use my grandfather as an example. He's always worked, every day of his life until he retired. Always had a car which, in his words "did what it needed to do".
So my dad offered to buy him a nice car - anything he could afford to run. He chose a 320d Touring X Drive. It had all the kit on it, and he loved it. Couple of years later, his health meant he struggled to get in and out of it, so he switched to a 2011 Tiguan. He's used to living within his means, so the Tiguan was the right option for him. He doesn't care for a badge/brand/engine. The Tiguan is higher, it's in white and it does 40 MPG, so he got it.
I went to see him recently, and let him drive my S5. The first thing he said was "it sounds bloody nice". He'd never get one in his current situation, but I KNOW that he'd get one (likely an SQ5 given his preference for higher cars) if he could afford one. It's just more exciting. Even for someone who is really happy with his Tiguan.
But he wouldn't buy an RSQ8, because he wouldn't value it any more than the SQ5 (just examples).
It's about the balance. Nice enough that you can appreciate something really nice, without spending outrageous money on something you won't notice as much.
Yes - Lee will likely find the A4 great. But I bet he'd find starting an S4 infinitely more exciting.
The point I'm trying to make is he should go and drive everything and anything, and buy the car which strikes the right balance between "this is
really nice" and "this is really expensive".
Don't spend 50 grand, but don't limit yourself to 15 when you're getting 10k in your bank tax free every month for 30 years.
Have some fun.