105 groupset £350, Mavic Ksyrium Elite £300, Tyres/Tubes £30, Bars/stem/seatpin - ITM/Deda say £150, Saddle - San Marco say £40, Peddals £50 = £920
Frame - the more you spend the better the quality.Don't compromise on fit = £1,000.
You will also need cycling shoes, bottle cages, computer, kit.
You can probably get cheaper prices by shopping around, buying last years models, some second hand.