FIrst of all, I truly believe that being able to generate pace must come naturally...and going to the gym and working out will only keep him fit. I just can't figure what correlation LK found b/w pace and gym!!! Good idea, but lacks proof. So lets drop it
Second, Shoaib has only pace, but lacks control over the ball. Yes sometimes pace is what's needed, it's also the swinging ball that you need to victimize specialist batsmen. Ballers with pace and no control can only bless the opponent with 4s and 6s (given the batsmen facing the bowler are specialist batsmen).
And finally, I don't think there's any correlation b/w pace and swinging ball pre se. Although, there is a relationship b/w pace and reverse swinging balls.