Shame you replaced parts without really having an idea where the issue is. That money could have gone into a spare box. First of all the starting issue is something that shouldn't happen. Find the cause of it and maybe you will gain power.

Check your timing, as its stock its a easy thing to do and you might gain hp

Its simple. Check if fuel path is good, check there are no air leaks and make sure iginition is fine. For sure you got trouble on fueling. So start there

I have run over 200bhp and the box never gave in. Now running 180 or sg and box is fine. If you break a box at around 180 bhp you shouldn't go for upgrade directly. Just take a next stock. If you break it you are just unlucky. And i know its your daily, but if you buy a del sol you buy somebody else his trouble. That car might fail you just as bad as the escort.