I don't know about the Volvo style but I put the Wilwood set up on the front of my 68 10+ years ago and overall am happy with them. My car is a driver. At the time it was about the same price as having my tired original 4 pistons re-worked but provided more pad area plus would be easy to take back to original if I decide to. I think if I had it to do over though I would look hard at the viability of trying to find some Mk X front brakes or look at Series II brakes so it would still be period style Jaguar. I have read that the bigger Mk X brakes is what they put on the Lightweight E-Types. My 2 cents
David Barnes
68 E-Type FHC