Nathan, the centre boss will require machining to accommodate the larger T25 diameter - 66.5mm I think.
The PCD is the same 5/112.
The ET, wheel offset, is too big - T4 is about 55 as far as I can recall , T25 about 35 so a 20mm adapter is required.
However, I found that if you fit an adapter you may not need to the machine the boss diameter!
Have you read this.....
http://www.brick-yard.co.uk/forum/defin ... c1290.html" onclick="window.open(this.href);return false;
Doug
PS Ian, at Syncro-nutz, had a pile of 15in rims that had been machined to fit the T25 with the correct ET , may be cheaper to buy a set of rims from him.
PPS Alternatively have a look at
http://www.kinkymicks.com/products.php?cPath=4" onclick="window.open(this.href);return false; although they may not be listed I'm sure he can get the adapter you need, that is 5/112 to 5/112, thickness is 23mm I think. I've had a couple of sets from him.