If the huffed tpi engine makes enough power for you just pull the trigger. There are all kinds of benefits to the LS like almost limitless power and drivability but you've got to install it and that is going to be a little more difficult and costly. You'll still have to plumb for injection with the tpi but that isn't difficult. Your 200r4 isn't an issue as it could go behind either engine. It isn't a daily so milage won't be a concern and how often are you actually going to autox it. If the engines cost the same, go that route unless you someday want a whole bunch more power - then go ls.