I'll try and answer your question as I run a VW passat.
The A4 is based on the golf floor pan, so it's there or there abouts the same (Passat A6). You'll pay more for the A4 than the Bora and the parts tend to be a tad more. If you can get the 'Red I' bora, as it has the 130 BHP engine and try to get a 6 speed much better all round, you might find it hard to find a 6 speed A4 in that plt, idealy you want a PD engine, loads of torque and good fuel returns, only produced them 2000 onwards. Also Audi are more to insure as the body panels etc cost Audi prices, I personally think in that plt the interior is not as good as the VW, but it's a personal thing, the latest Audi out strips the lastest VW interior so there you go. Another thing is there are more VW about second hand than Audi as they were cheaper to buy and company car suppliers look at costs.
Hope it helps.
What the gentleman means is do I want an E Class or a C?
Personally I'd go for the E (Coz I can and have) and enjoy yourself
Don't touch that VAG stuff, you'll regret it
The Audi A4 is a Passat, only differences are the badge and some interior trim. The only good thing about VW is they managed to turn around a duff company like Skoda and actually give it a good name.Bora or A4, well the A4. A Bora is just a Golf with a boot, and the A4 is PAssatt sized.
Personal choice would be A4. Servicing costs more than a VW but parts are pretty generic, however I wouldn't like to guess at which is more reliable. Audis tend to be better built.