not to mention that lowering your car by going with smaller diameter tires *really* throws your speedometer out of wack. Case in point, I had a pick-up back in the late 80's/early 90's that I lowered and put smaller (i.e. lower profile) tires on. Stock was 195/75 14, I had to switch to 185/60 14 (the lowest profile tire for a 14 inch rim at the time) for fender clearance, and my speedometer was so far out of wack that it read 15 to 20MPH faster than what I was actually traveling at. I know this because I was pulled over for no rear bumper (I grew up in FL) I was going "60" in a 45 according to my speedometer but the officer said I was spot on with the speed limit.
Also, a 45 series 14" tire? Do those actually exist? I mean the side wall profile on a 185/60 is in the 1.5" to 2" range, and when stretched out over a 7" wide rim it's pretty low, and are at least 2 - 3" shorter in height than a 70 series tire (equalling 1 to 1.5 lower stance).
At any rate, the more mechanically sound method is to go with lowered springs and/or coil-over conversion kit... Or even better (for later "raised" MGs) adapt the front cross member w/ suspension components from the early model B's. And if you wish to go with a lower profile tire then it's a good idea to make up the tire size (diameter) difference with a larger rim, just to reduce the chances of throwing the rest of your drive train out of wack.
Personally, when i get the time and get everything else corrected with my 'B I'll be lowering the car's suspension with springs and then stepping up to a 15x5.5" or 15x6" rim with 195/60s