Coolant Overflow Tank Options....

If you don't need the washer reservoir, you can use that. The coolant sensor even can reportedly be made to fit and function.

Others have tossed a skinny aluminum can to the front of the radiator support. 95Cobraguy put up pics of his once IIRC.

The overflow bottle contents are at 1 Atm. You just need a cap to keep debris out (most OEM overflows even have a vent hole in case of overfilling). Ours included as I recall (there's a snout near the top of the bottle IIRC).

i was going to mention using the washer reservoir too. if you don't ever plan on using your washer fluid, that would be your best bet.

i posted on the other board. but yea i have one of the cheap summit ones. works fine.

95cobraguy runs a $30 moroso catch can, and he mounted it in front of the radiator mounted from the rad support. it's basiclly under the radiator support cover.
i wanted to do the same but realized that if i ever get this turbo kit in the intercooler would mount there so i have to look at other options.

EDIT: IIRC this is the moroso that he uses, but my memmory might be off. Moroso 63657 - Moroso Radiator Overflow Tanks