tsp catted y-pipe

[brp57]

trying to install tsp catted y-pipe and i knew it was going to be a paid in the ass. Figured i would run this idea across you guys 1st. I was thinking about cutting the I-pipe about 1 foot (from where they should meet), then mock up the y-pipe to where i want it for the most part, then modify the I pipe (cut) to butt fit and then maybe tack weld and use a 3" band clamp. Do you think it would hold fine with just the band clamp, or should i tack weld it also. any additional info would be great.

Problem is I dont want to take the cat-back apart/off for hooker quality reasons.

[SMWS6TA]

I used band clamps for a yr until I went and weld up the ORY. It will still leak a little but...for the short term I lived with it.