Listen to TigBitties over here. Basemaps are guesses, and like bloodshot stated- they will at best allow you to drive your car and maybe smooth out a few bumps. It isn't worth the risk to have built something up just to take it down again...whether you are made of gold or not, that should be taken into consideration.
Also, yes. "street" tuning can save you a lot of money but at a cost. It is unsafe and would require many conditions. for example: 1)Two people, one to operate your ecu tuning program/flash and the other to drive the car. 2) a long, wide open, desolate place for long runs during the tuning process. 3) the person doing the tune on the program must be knowledgeable of how it is used efficiently and have a vast amount of understanding of the said combustion set up to get the motor to its safest max output.
Problems with these are: 1)Speed limits, whether you do this at 12 midnight or any where you have a speed limit to obey. Say you get caught and that's a ticket + under hood inspection (hopefully its a carb legal turbo)...And if you obey speed limit, you aren't truly tuning the ecu to its highest/safest output which means it would still be spotty. 2) if you want to do the tune you are going to have to do said research and learn how to use a brand new program, the risk? do a wrong map set up and you could ruin it. 3) if the other guy does it, you aren't really learning it are you? yeah you may save a buck but wasn't the whole point to learn a valuable asset? Sure he can teach you, but the risk remains as the previous said risk.
Do a Dyno tune, Here you can push it to the limits and get the best map set up. no worrying about speed limits or damaging (unless it is a crappy uncertified tuner...I agree that there are excellent uncertified tuners out there but that is you can find/trust one) Also, your tuner can explain everything he did during the tune and explain why. This is useful to you because if you want to eventually do a street tune, you have clear information on how the basics work. Also, nothing says that this guy wont reach out a hand to you and teach you how to tune it yourself....its all about the connections
: Mitchwbr. You need a tune and there isn't anyway around it, a bleeder valve can only help you keep boost pressure very low so that it doesn't spike/peak, resulting in you blowing up the engine, while on your way to a tuner or an emergency. I didn't recommend it as a fix or anything of the sort, I said that the only thing that has any type of toggle like what you were looking for is an electronic bleeder and at best it may provide help.