Couple of things i forgot to point out...
Modding a car on PCP is technically frowned upon as the finance house have an interest in the car until at the very least the halfway stage, never stopped me although i dont go mad with the mods on any car tbh and it's never presented a problem and the VW dealers never bat an eyelid, keep up the payments and dont hand it back dragging its arse on coilies and running stage 3 and it's usually fine lol
I do however remember a guy on seatcupra.net who had a very heavily modded MK2 Cupra which developed an ECU/starting fault after an intercooler fit, had it towed to Seat and demanded they fix it under warranty etc, got a bit shouty when they couldnt and then threw his toys out at them, they retaliated by throwing their toys out and demanding he return their car to standard and pay the remaining finance, so play nice is the moral of that story lol!
Also you are not obliged to take the PCP through VW/Audi etc, there are plenty of 3rd party companies who will fund the deal on PCP via the supplying dealer on your behalf and you can use this facility to get a better deal from the dealer or simply get a better deal from the 3rd party...
As with any finance deal, resist the temptation to have the road tax/gap/autosh*te etc thrown on the deal as you'll pay interest on it all and just make sure you go over ever aspect of the deal a good few times before pulling the trigger
PCPs are in no way the golden egg of cheap car buying but can work extremely well on the right car and personal circumstances, for me they retain monthly affordability and some stability of the car value in what is an uncertain market but i appreciate that some people will find the idea of a PCP off putting