help ... 33's and gearing

I'm going to buy some new tyres for my Disco 1 and I'm 90% sure they are going to be Maxxis buckshot mudders 285/75/16's (metric equiv to 33's) because of the price and usability on road and the good reviews I've read about them for offroad .... I commute 50 motorway miles and was wondering what they will be like in 5th ? Will my 300 tdi struggle ?
Cheers

It'll be fine, just tweak the fuel pump - makes the world of difference.

i got used to 33's on mine, but recently put road tyres on and you realise how much of a difference they make with the gearing. but if you tweak the pump it can easily be lived with. mine just struggles to accelerate at 70 when on a gentle hill

Thanks for the quick replies ... I've already tweaked the fuel pump and removed/blanked the EGR as long as it'll sit at 60 thats all I'm bothered about ... anymore is scary with the lift on

Mine will do 70+ on 31's so 60 should be no problem on 33