no

YES ! Very important or your insurance will be void ! You must buy rated tyres ! Like for eg... Falken do a basic 103W which are load rated to 875kg (1929lbs) which is more than you require.
The lowest cheapest `load rated tyre` you can put on would be 99W. As for the size etc that all depends on what wheel you have to start with. Goto `rochford tyres` website they have plenty of info charts etc on there to inform you.
Regards Mike.

Umm... I'm not sure where the above got his information... My source here shows a suggested load rating of 102 and suggested speed rating of H as per original manufacturer recomendation for the '03 Eurovan (All trim levels)... Size should be 225/60R16 with a 102H or better load/speed rating...

This isn't 'special' just what your car takes.  It is however a slightly unusual size for that kind of load rating so what ever shop you plan to have mount/balance them will likely need to special order them, as they are not likely to be kept in stock.

M 81 mph 130 km/h  
N 87 mph 140km/h Temporary Spare Tires
P 93 mph 150 km/h  
Q 99 mph 160 km/h Studless & Studdable Winter Tires
R 106 mph 170 km/h H.D. Light Truck Tires
S 112 mph 180 km/h Family Sedans & Vans
T 118 mph 190 km/h Family Sedans & Vans
U 124 mph 200 km/h  
H 130 mph 210 km/h Sport Sedans & Coupes
V 149 mph 240 km/h Sport Sedans, Coupes & Sports Cars
W 112 mph 180 km/h Commercial load rated, Light vans

As for a `van` carrying weight/load the load rating needs to be over `just` 102H as thats a rating only upto that speed and not to carry the weight as well. Or `C` for commercial rating.
Thats why you bring the next ratings into force like for eg. 103W `Weight` The `H` rating is not needed on a van as not many get up to those kind of speeds...

But then again these are all `laws` in `England` and my guess by the way your spelling `tyres` (tires) Are that your American ?
Did a lot of research into the buying of tyres because i have the VW T5 2004 so had to get suitable tyres (tires)
Regards Mike.

True in all respects...
I just found it odd that you were recommending a higher load rating than what comes on the vehicle here( dunno if it's the same here as there) and yet a lower speed rating... Hence why I said I'm not sure where you got your numbers.

The fitment guide I have only shows what the vehicle was (supposedly) equipped with originally here.

I think it's standard here for a vehicle to receive a speed rating ruffly equal to what the vehicle is capable of, not necessarily what it will ever see.  I just always repeat what the manufacturer recommended since I'm by no means a tire expert, and sticking to the original is a good way to avoid giving out bad information.