Trust me, you can win a TTS without a BAR. You just need to be very good with the weapon you are using, and have a lot of experience in spar. And I'm sure this problem was addressed before when someone made PBP illegal in events, and a lot of people said that 1 equal gun for everyone to use would be much more fair. But then it's unfair as each player is adapted to their favourite weapon, which they'll use in TTS. Just take BabyGhost for an example lol.
I understand it can get frustrating losing events, but just keep practicing. Every 'pro' at events was always once a noob, but that constant practice, experience makes you better, and before you know it, you'll be winning ecs at a regular basis. As for Tag Team Spar or Spar Tournament, just practice sparring in Underground/Complex Spar, and especially in Gang Spar. Helps out a lot.