I'd concur with what's been said already. You have the JTDm so the later injectors (and I think ECU, with its many adjustable paramaters) will allow close to 200bhp. But what really counts in a diesel remap is the torque. And this is what will put your transmission under strain. You can't rely on the standard diff to take it, so you'll need a Q2 or a Quaife (the gearbox should be fine, that's effectively the GTA gearbox). Your clutch will likely go pretty quick if you use the grunt frequently, so you'd be better off with a Cloverleaf clutch, or some other aftermarket uprated one. The driveshafts will hopefully be OK, so long as you don't muller it too much out of corners.
I have 192bhp and 330 ft/lbs and the performance is pretty damn good for the car. I think anything much more than that, and as well as new exhaust/induction/turbo, you're looking at a new suspension set up, as well as a new, uprated brake system. It could get very expensive.